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1.	Alam, Mohammad Anzar, et al. (författare) Limitation of a line-of-light online paper surface measurement system 2014 Ingår i: IEEE Sensors Journal. - 1530-437X .- 1558-1748. ; 14:8, s. 2715-2724 Tidskriftsartikel (refereegranskat)abstract A new prototype device has been developed based on a laser triangulation principle to measure online surface topography in the paper and paperboard industries. It characterizes the surface in a wide spatial scale of topography from 0.09-10 mm. The prototype's technique projects a narrow line-of-light perpendicularly onto the moving paper-Web surface and scattered reflected light is collected at a low angle, low specular, and reduced coherent length onto the CCD sensors synchronized with the laser sources. The scattering phenomenon determines surface deviations in the z-direction. The full-width, at half-maximum of a laser line in cross section is sensitive in computation of the surface topography. The signal processing aspect of the image processing, for example, threshold and filtering algorithms are also sensitive in estimating the accurate surface features. Moreover, improper light illumination, intensity, reflection, occlusion, surface motion, and noise in the imaging sensor, and so forth, all contribute to deteriorate the measurements. Optical techniques measure the surface indirectly and, in general, an evaluation of the performance and the limitations of the technique are both essential and challenging. The paper describes the accuracy, uncertainty, and limitations of the developed technique in the raw profiles and in terms of the rms roughness. The achieved image subpixel resolution is 0.01 times a pixel. Statistically estimated uncertainty (2σ) in the laboratory environment was found 0.05 μm for a smooth sample, which provides a 95% confidence level in the rms roughness results. The depth of field of the prototype is ~2.4 mm.
2.	Alam, Mohammad Anzar, et al. (författare) Real time surface measurement technique in a wide range of wavelengths spectrum 2014 Ingår i: IEEE Sensors Journal. - 1530-437X .- 1558-1748. ; 14:1, s. 285-294 Tidskriftsartikel (refereegranskat)abstract Real time surface topography measurement in the paper and paperboard industries is a challenging research field. The existing online techniques measure only a small area of paper surface and estimate topographical irregularities in a narrow scale as a single predictor. Considering the limitations and complications in measuring the surface at high speed, a laser line triangulation technique is explored to measure surface topography in a wide scale. The developed technique is new for the paper and paperboard application that scans a line onto the paper-web surface up to 210 mm in length in the cross machine direction. The combination of a narrow laser linewidth imaging, a subpixel resolution, and the selection of a unique measurement location has made it possible to measure roughness and simultaneously characterize paper surface topography from 0.1 to 30 mm spatial wavelength. This spatial range covers wide scale surface properties such as roughness, cockling, and waviness. The technique clearly distinguishes and characterizes the surface of newspaper, and lightweight coated, coated, and uncoated paperboard in real time during the paper manufacturing process. The system temporal noise for the average roughness is estimated as 37 dB. The signal to noise ratio found is from 5.4 to 8.1 in the short spatial wavelength up to 1 mm, whereas it is more than 75 in the long spatial wavelength from 5 to 10 mm.
3.	Andersson, Henrik, et al. (författare) Inkjet printed silver nanoparticle humidity sensor with memory effect on paper 2012 Ingår i: IEEE Sensors Journal. - 1530-437X .- 1558-1748. ; 12:6, s. 1901-1905 Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract In this paper, the design and the manufacture of an inkjet printed resistive type humidity sensor on paper are reported. After having been exposed to humidity above a given threshold level, the resistance of the sensor decreases substantially and remains at that level even when thehumidity is reduced. It is possible to deduce the humidity level by monitoring the resistance. The main benefit of the printed sensor presented in this case is in relation to its very low production costs. It has also been shown that both the ink type and this paper combination used prove to be crucial in order to obtain the desired sensor effect. More research is required in order to fully understand the humidity sintering effect on the nano particle ink and the role of the substrate. However, the observed effect can be put to use in printed humidity sensors which possess a memoryfunction. The sensor can be used in various applications for environmental monitoring, for example, in situations where a large number of inexpensive and disposable humidity sensors are required which are able to detect whether they have been subjected to high humidity. This could be the checking of transportation conditions of goods or monitoring humidity within buildings. © 2001-2012 IEEE.
4.	Andersson, Henrik, et al. (författare) Investigation of Humidity Sensor Effect in Silver Nanoparticle Ink Sensors Printed on Paper 2014 Ingår i: IEEE Sensors Journal. - 1530-437X .- 1558-1748. ; 14:3, s. Art. no. 6615915- Tidskriftsartikel (refereegranskat)abstract Thin inkjet-printed tracks of silver nanoparticles have previously been observed to show a non-reversible decrease in resistance when exposed to a high degree of relative humidity and thus providing sensor functionality with a memory effect. This paper provides a more in-depth explanation of the observed humidity sensor effect that originates from inkjet-printed silver nanoparticle sensors on a paper substrate. It is shown that the geometry of the sensor has a large effect on the sensor's initial resistance, and therefore also on the sensor's resistive dynamic range. The importance of the sensor geometry is believed to be due to the amount of solvent from the ink interacting with the coating of the paper substrate, which in turn enables the diffusion of salts from the paper coating into the ink and thus affecting the silver ink.
5.	Anderås, Emil, 1982-, et al. (författare) Tilted c-Axis Thin-Film Bulk Wave Resonant Pressure Sensors With Improved Sensitivity 2012 Ingår i: IEEE Sensors Journal. - 1530-437X .- 1558-1748. ; 12:8, s. 2653-2654 Tidskriftsartikel (refereegranskat)abstract Aluminum nitride thin film bulk wave resonant pressure sensors employing c- and tilted c-axis texture, have been fabricated and tested for their pressure sensitivities. The c-axis tilted FBAR pressure sensors demonstrate substantially higher pressure sensitivity compared to its c-axis oriented counterpart. More specifically the thickness plate quasi-shear resonance has demonstrated the highest pressure sensitivity while further being able to preserve its performance in liquid environment.
6.	Arapan, Lilia, et al. (författare) Sensitivity Features of Thin Film Plate Acoustic Wave Resonators 2011 Ingår i: IEEE Sensors Journal. - : IEEE Sensors Council. - 1530-437X .- 1558-1748. ; 11:12, s. 3330-3331 Tidskriftsartikel (refereegranskat)abstract Thin film plate acoustic resonators devices operating in the lowest order symmetric Lamb wave mode (S0) in coriented aluminum nitride (AlN) membranes on Si were fabricated and tested for their sensitivities to pressure and mass as well as for their ability to work in liquid environment.
7.	Athalye, Akshay, et al. (författare) Novel Semi-Passive RFID System for Indoor Localization 2013 Ingår i: IEEE Sensors Journal. - 1530-437X .- 1558-1748. ; 13:2, s. 528-537 Tidskriftsartikel (refereegranskat)abstract In this paper, we present a novel semi-passive radio-frequency identification (RFID) system for accurate indoor localization. The system is composed of a standard ultra high frequency (UHF) ISO-18000-6C compliant RFID reader, a set of standard passive RFID tags whose locations are known, and a newly developed tag-like RFID component, which is attached to the items that need to be localized. The new semi-passive component, referred to as sensatag (sense-a-tag), has a dual functionality: it can sense and decode communication between the reader and standard tags in its proximity, and can communicate with the reader like standard tags using backscatter modulation. Based on the information conveyed by the sensatags to the reader, localization algorithms based on binary sensor principles can be developed. We conduct a number of experiments in a laboratory to quantify the performance of our system, including two real applications, one finding the exact placement of items on shelves, and the other estimating the direction of item movement.
8.	Barac, Filip, 1983-, et al. (författare) Channel Diagnostics for Wireless Sensor Networks in Harsh Industrial Environments 2014 Ingår i: IEEE Sensors Journal. - 1530-437X .- 1558-1748. ; 14:11, s. 3983-3995 Tidskriftsartikel (refereegranskat)abstract Wireless sensor network communication in industrial environments is compromised by interference, multipath fading, and signal attenuation. In that respect, accurate channel diagnostics is imperative to selecting the adequate countermeasures. This paper presents the lightweight packet error discriminator (LPED) that infers the wireless link condition by distinguishing between errors caused by multipath fading and attenuation, and those inflicted by interfering wideband single-channel communication systems (e.g., IEEE 802.11b/g), based on the differences in their error footprints. The LPED uses forward error correction in a novel context, namely, to determine the symbol error density, which is then fed to a discriminator for error source classification. The classification criteria are derived from an extensive set of error traces collected in three different types of industrial environments, and verified on a newly collected set of error traces. The proposed solution is evaluated both offline and online, in terms of classification accuracy, speed of channel diagnostics, and execution time. The results show that in ≥91% of cases, a single packet is sufficient for a correct channel diagnosis, accelerating link state inference by at least 270%, compared with the relevant state-of-the-art approaches. The execution time of LPED, for the worst case of packet corruption and maximum packet size, is below 30 ms with ≤3% of device memory consumption. Finally, live tests in an industrial environment show that LPED quickly recovers from link outage, by losing up to two packets on average, which is only one packet above the theoretical minimum.
9.	Becker, Elin, et al. (författare) Study of the Sensing Mechanism Towards Carbon Monoxide of Platinum-Based Field Effect Sensors 2011 Ingår i: IEEE SENSORS JOURNAL. - : IEEE. - 1530-437X. ; 11:7, s. 1527-1534 Tidskriftsartikel (refereegranskat)abstract We have investigated the temperature dependence and the effect of hydrogen on the CO response of MISiC field effect device sensors. The evolution of adsorbates on a model sensor was studied by in situ DRIFT spectroscopy and correlated to sensor response measurements at similar conditions. A strong correlation between the CO coverage of the sensor surface and the sensor response was found. The temperature dependence and hydrogen sensitivity are partly in agreement with these observations, however at low temperatures it is difficult to explain the observed increase in sensor response with increasing temperature. This may be explained by the reduction of a surface oxide or removal of oxygen from the Pt/SiO2 interface at increasing temperatures. The sensing mechanism of MISiC field effect sensors is likely complex, involving several of the factors discussed in this paper.
10.	Becker, Elin, 1981, et al. (författare) Study of the Sensing Mechanism Towards Carbon Monoxide of Platinum-Based Field Effect Sensors 2011 Ingår i: IEEE Sensors Journal. - : Institute of Electrical and Electronics Engineers (IEEE). - 1558-1748 .- 1530-437X. ; 11:7, s. 1527-1534 Tidskriftsartikel (refereegranskat)abstract We have investigated the temperature dependence and the effect of hydrogen on the CO response of MISiC field effect device sensors. The evolution of adsorbates on a model sensor was studied by in situ DRIFT spectroscopy and correlated to sensor response measurements at similar conditions. A strong correlation between the CO coverage of the sensor surface and the sensor response was found. The temperature dependence and hydrogen sensitivity are partly in agreement with these observations, however at low temperatures it is difficult to explain the observed increase in sensor response with increasing temperature. This may be explained by the reduction of a surface oxide or removal of oxygen from the Pt/SiO2 interface at increasing temperatures. The sensing mechanism of MISiC field effect sensors is likely complex, involving several of the factors discussed in this paper.
11.	Bur, Christian, et al. (författare) Detecting Volatile Organic Compounds in the ppb Range with Gas Sensitive Platinum gate SiC-Field Effect Transistors 2014 Ingår i: IEEE Sensors Journal. - 1530-437X .- 1558-1748. ; 14:9, s. 3221-3228 Tidskriftsartikel (refereegranskat)abstract In this paper, the use of a platinum gate gas-sensitive SiC field-effect transistor (SiC-FET) was studied for the detection of low concentrations of hazardous volatile organic compounds (VOCs). For this purpose, a new gas mixing system was realized providing VOCs down to sub-parts per billion levels with permeation ovens and gas predilution. Benzene, naphthalene, and formaldehyde were chosen as major indoor air pollutants and their characteristics are briefly reviewed. Measurements have shown that the selected VOCs can be detected by the SiC-FET in the parts per billion range and indicate a detection limit of ~1 ppb for benzene and naphthalene and ~10 ppb for formaldehyde in humid atmospheres. For 10-ppb naphthalene at 20% r.h., the sensor response is high with 12 mV, respectively, a relative response of 1.4%. Even in a background of 2-ppm ethanol, the relative response is still 0.3%. Quantification independent of the humidity level can be achieved using temperature cycled operation combined with pattern recognition, here linear discriminant analysis. Discrimination of benzene, naphthalene, and formaldehyde is also possible.
12.	Bur, Christian, et al. (författare) Increasing the Selectivity of Pt-Gate SiC Field Effect Gas Sensors by Dynamic Temperature Modulation 2012 Ingår i: IEEE Sensors Journal. - : Institute of Electrical and Electronics Engineers (IEEE). - 1530-437X .- 1558-1748. ; 12:6 Tidskriftsartikel (refereegranskat)abstract Based on a diode coupled silicon carbide field effect transistor (FET) with platinum as catalytic gate material, the influence of dynamic temperature modulation on the selectivity of gas analysis sensors FETs has been investigated. This operating mode, studied intensively for semiconductor gas sensors, has only recently been applied to FETs. A suitable temperature cycle for detection of typical exhaust gases (CO, NO, C3H6, H-2, NH3) was developed and combined with appropriate signal processing. The sensor data were evaluated using multivariate statistics, e.g., linear discriminant analysis. Measurements have proven that typical exhaust gases can be discriminated in backgrounds with 0, 10, and 20% oxygen. Furthermore, we are able to quantify the mentioned gases and to determine unknown concentrations based on training data. Very low levels of relative humidity below a few percent influence the sensor response considerably but for higher levels the cross interference of humidity is negligible. In addition, experiments regarding stability and reproducibility were performed.
13.	Cheng, Peng, et al. (författare) Stator-free RPM Sensor Using Accelerometers - A Statistical Performance Simulation by Monte Carlo Method 2011 Ingår i: IEEE Sensors Journal. - 1530-437X .- 1558-1748. ; 11:12, s. 3368-3376 Tidskriftsartikel (refereegranskat)abstract This paper presents an statistical performance simulation for rigid-body revolutions per minute (RPM) measurement based on two uni-axial accelerometers mounted on rotor. In comparison with other existing sensing methods that are based on two coupled parts, namely stator and rotor and which include conventional electro-magnetic RPM sensors and photo-electric RPM sensors, this new stator-free inertial sensing principle has the advantage of high bandwidth at low RPM, true contact-free sensing and flexible installation. The paper first focuses on the description of the operating principle and the common mode rejection (CMR) method of the stator-free RPM sensor, and then its error model is developed and the error sources are statistically simulated based on Monte Carlo method. The simulation result presents a most interesting property of this sensor, that is, it gives lower precision at lower RPM and higher precision at higher RPM. The conclusion summarizes the modeling analysis result and motivates potential application for this new RPM sensing method.
14.	Concina, Isabella, et al. (författare) Electronic Noses as Flexible Tools to Assess Food Quality and Safety: Should We Trust Them? 2012 Ingår i: IEEE Sensors Journal. - 1530-437X .- 1558-1748. ; 12:11, s. 3232-3237 Tidskriftsartikel (refereegranskat)
15.	Enlund, Johannes, et al. (författare) FBAR sensor array for in liquid operation 2010 Ingår i: IEEE Sensors Journal. - 1530-437X .- 1558-1748. ; 10:12, s. 1903-1904 Tidskriftsartikel (refereegranskat)abstract This letter discusses the design of thickness shear mode thin-film bulk acoustic resonator (FBAR) sensor array for in liquid operation with respect to minimizing the observed Q-degradation and crosstalk.
16.	Feng, Yi, et al. (författare) Flexible UHF resistive humidity sensors based on carbon nanotubes 2012 Ingår i: IEEE Sensors Journal. - 1530-437X .- 1558-1748. ; 12:9, s. 2844-2850 Tidskriftsartikel (refereegranskat)abstract This paper presents the investigation of the resistive humidity-sensing properties of multi-walled carbon nanotubes (MWCNTs). MWCNTs functionalized by acid treatment (f-MWCNTs) exhibit rather high sensitivity in resistance toward humidity, owing to the presence of carboxylic groups on the nanotube surface. By integrating the f-MWCNTs resistor into a wireless sensor platform, flexible humidity sensors for ultra-high frequency applications are investigated. The operating frequency range of the sensor is dramatically increased from 600 MHz to 2 GHz by adjusting the resistor-electrodes' configuration. This enhancement is predominately attributed to the variation in parasitic capacitance between the resistor-electrodes.
17.	Fu, Hongyan, et al. (författare) Transversal-Load Sensor by Using Local Pressure on a Chirped Fiber Bragg Grating 2010 Ingår i: IEEE Sensors Journal. - : Institute of Electrical and Electronics Engineers (IEEE). - 1530-437X .- 1558-1748. ; 10:6, s. 1140-1141 Tidskriftsartikel (refereegranskat)abstract A transversal-load sensor based on the local pressure-induced refractive index change in a chirped fiber Bragg grating (CFBG) is proposed. The local pressure induced refractive index change in the touch point can generate a main transmission peak and several subpeaks on the long wavelength side of the reflection band of the CFBG. The difference of the wavelength shifts for the main transmission peak and the first subpeak is used to measure transversal-load with temperature compensation capability.
18.	Gao, Jinlan, et al. (författare) Printed Humidity Sensor with Memory Functionality for Passive RFID tags 2013 Ingår i: IEEE Sensors Journal. - 1530-437X .- 1558-1748. ; 13:5, s. 1824-1834 Tidskriftsartikel (refereegranskat)abstract This paper presents a printed UHF RFID sensor solution that indicates whether a passive RFID tag has been exposed to a certain degree of humidity. The printed sensor operates as a Write Once Read Many (WORM) resistive memory as it permanently changes its resistance from about 2 kÙ to less than 50 Ù after exposure to humidity or water. The change of the sensor resistance is used to modulate the properties of a UHF RFID tag antenna by changing antenna input impedance and also introducing or removing ohmic losses in the antenna structure. The final result is reflected in the change of the minimum transmit power required to power-up the RFID tag. Both the sensor and the tag antenna are printed horizontally on a paper substrate. Different geometric combinations of sensor and antenna structures are investigated. Typical applications include non-invasive methods for detecting wetness or humidity levels in hidden locations such as within construction structures. The sensor setup can also serve to provide information as to whether a package sent over a supply chain has exceeded a certain level of humidity during its route.
19.	Gingl, Zoltan, et al. (författare) Fluctuation-Enhanced Sensing With Zero-Crossing Analysis for High-Speed and Low-Power Applications 2010 Ingår i: IEEE Sensors Journal. - 1530-437X .- 1558-1748. ; 10:3, s. 492-497 Tidskriftsartikel (refereegranskat)abstract A new method to generate fingerprints of chemical agents has been introduced in this paper. The method is based on the use of the zero-crossing statistics at fluctuation-enhanced sensing. It is a new version of Ben Kedem's original method based on low-pass filters. To improve computation time and energy efficiency, high-pass filtering is used, and in doing this in the simplest possible way, local zero levels for short-time subwindows are defined and a zero-crossing counting by the use of such windows is carried out. The method turns out to be an effective tool to identify noise processes with different spectra or amplitude distribution, with at least 1000 times less calculation and correspondingly lower energy need than that of the Kedem or the fast Fourier transform methods. We demonstrate the usability of the method by the analysis and recognition of different stochastic processes with similar and different spectra.
20.	Hök, Bertil, et al. (författare) Breath Analyzer for Alcolocks and Screening Devices 2010 Ingår i: IEEE Sensors Journal. - 1530-437X .- 1558-1748. ; 10, s. 10-15 Tidskriftsartikel (refereegranskat)abstract Alcolocks and alcohol screening devices are becoming commonplace, and their use is expected to grow rapidly with cost reduction and improved usability. A new breath analyzer prototype is demonstrated, with the prospects of eliminating the mouthpiece, reducing expiration time and volume, improving long-term stability, and reducing life cycle cost. Simultaneous CO2 measurements compensate for the sample dilution and unsaturated expiration. Infrared transmission spectroscopy is used for both the alcohol and CO2 measurement, yet the entire system is contained within a small handheld unit. Experimental results are reported on the device sensitivity, linearity, resolution, and influence from varying measuring distance. The correlation between early and full-time sampling was established in 60 subjects. Basic concept verification was obtained, whereas resolution and selectivity still needs to be improved. Further improvements are expected by system optimization and integration.
21.	Larsson, Andreas, et al. (författare) Thermal Management System for Particle Sensors Design, Performance and Verification 2012 Ingår i: IEEE Sensors Journal. - : Institute of Electrical and Electronics Engineers (IEEE). - 1530-437X .- 1558-1748. ; 12:6, s. 2299-2305 Tidskriftsartikel (refereegranskat)abstract This paper presents the thermal performance of a proposed thermal management device (patented in 2009) intended for a thermophoresis-based soot sensor. The performance was studied for temperatures ranging from 50 to 400 degrees C and for exhaust speeds up to 10 m/s. It also presents the design and basic concepts. The performance study and design development were performed with finite element analysis (FEA). The FEA results were then verified with experiments in a heated wind tunnel. The relative performance of the device was found to increase for higher temperatures and lower wind speeds. The main conclusion drawn from this paper was that it is feasible to cool a sensor surface enough for a thermophoresis-based soot sensor in a diesel exhaust system.
22.	Le, Anhtuan, et al. (författare) The Impact of Rank Attack on Network Topology of Routing Protocol for Low-Power and Lossy Networks 2013 Ingår i: IEEE Sensors Journal. - Piscataway, NJ : IEEE Press. - 1530-437X .- 1558-1748. ; 13:10, s. 3685-3692 Tidskriftsartikel (refereegranskat)abstract Routing protocol for low power and lossy networks (RPL) is the underlying routing protocol of 6LoWPAN, a core communication standard for the Internet of Things. RPL outperforms other wireless sensor and ad hoc routing protocols in quality of service (QoS), device management, and energy saving performance. The Rank concept in RPL serves multiple purposes, including route optimization, prevention of loops, and managing control overhead. In this paper, we analyze several different types of internal threats that are aimed at the Rank property and study their impact on the performance of the wireless sensor network. Our analysis raises the question of an RPL weakness, which is the lack of a monitoring parent in every node. In RPL, the child node only receives the parent information through control messages, but it cannot check the services that its parent provide hence it will follow a bad quality route if it has a malicious parent. Our results show that different types of the Rank attacks can be used to intentionally downgrade specific QoS parameters. This paper also reveals that attack in a high forwarding load area will have more impact on network performance than attack in other areas. The defenders can use the knowledge of such correlation between attack location and its impact to set higher security levels at particular positions by monitoring sensitive network parameters and detecting the anomalies © 2001-2012 IEEE.
23.	Nilsson, Hans-Erik, et al. (författare) Printed write once and read many sensor memories in smart packaging applications 2011 Ingår i: IEEE Sensors Journal. - 1530-437X .- 1558-1748. ; 11:9, s. 1759-1767 Tidskriftsartikel (refereegranskat)abstract A horizontal printed Write Once Read Many (WORM) resistive memory has been developed for use in wireless sensortags targeting single event detection in smart packaging applications. The WORM memory can be programmed using a 1.5 V printedbattery. An alternative programming method is to use chemical sintering which allows the development of exposure-time triggeredsingle event tags that can be accessed wirelessly. The new WORM memory has very low losses in the ON-state which allows directintegration into antenna structures.A sensor tag that utilizes the WORM memory functionality and the well established Electronic Article Surveillance (EAS)communication standard has been outlined. Both active and fully passive sensor tag solutions have been proposed.The role of printed electronics in smart packaging applications has been reviewed and discussed. Important enabling factors forthe future development have been highlighted, such as the need for hierarchical design and test tools, better printed interconnecttechnologies as well as better components that allow communication with existing information and communication technology (ICT)standards. This is illustrated and underlined by the presented smart packaging concept demonstrators.
24.	Palmer, Kristoffer, 1983-, et al. (författare) Two-Dimensional Thermal Velocity Sensor for Submersible navigation and Minute Flow Measurements 2013 Ingår i: IEEE Sensors Journal. - 1530-437X .- 1558-1748. ; 13:1, s. 359-370 Tidskriftsartikel (refereegranskat)abstract A 2-D thermal velocity microsensor for use as a navigational aid and for flow measurements on a miniaturized submersible is developed in this paper. The sensor with nickel heater and temperature sensors on a Pyrex substrate, designed for mounting on the outside of the submersible hull, is fabricated and tested in an application-like environment and proven to be able to measure water speed from zero to 40 mm/s with a power consumption less than 15 mW and determine the flow direction with an error less than ±8°. Finite Element Analysis is used to investigate design and operation parameters and possible biofouling effects on the sensor signal. The effect on shape and orientation of the sensor's mounting surface is also studied.
25.	Raza, Shahid, 1980-, et al. (författare) Lithe: Lightweight Secure CoAP for the Internet of Things 2013 Ingår i: IEEE Sensors Journal. - 1530-437X .- 1558-1748. ; 13, s. 3711-3720 Tidskriftsartikel (refereegranskat)abstract The Internet of Things (IoT) enables a wide range of application scenarios with potentially critical actuating and sensing tasks, e.g., in the e-health domain. For communication at the application layer, resource-constrained devices are expected to employ the Constrained Application Protocol (CoAP) that is currently being standardized at the IETF. To protect the transmission of sensitive information, secure CoAP (CoAPs) mandates the use of Datagram TLS (DTLS) as the underlying security protocol for authenticated and confidential communica- tion. DTLS, however, was originally designed for comparably powerful devices that are interconnected via reliable, high- bandwidth links.In this paper, we present Lithe – an integration of DTLS and CoAP for the IoT. With Lithe, we additionally propose a novel DTLS header compression scheme that aims to significantly reduce the header overhead of DTLS leveraging the 6LoWPAN standard. Most importantly, our proposed DTLS header com- pression scheme does not compromise the end-to-end security properties provided by DTLS. At the same time, it considerably reduces the number of transmitted bytes while maintaining DTLS standard compliance. We evaluate our approach based on a DTLS implementation for the Contiki operating system. Our evaluation results show significant gains in terms of packet size, energy consumption, processing time, and network-wide response times, when compressed DTLS is enabled.
26.	Rosental, Arnold, et al. (författare) Epitaxial Single and Double Nanolayers of SnO2 and TiO2 for Resistive Gas Sensors 2013 Ingår i: IEEE Sensors Journal. - 1530-437X .- 1558-1748. ; 13:5, s. 1648-1655 Tidskriftsartikel (refereegranskat)abstract Rutile TiO2 (1 0 1) and cassiterite SnO2 (1 0 1) epitaxial single and double nanolayers, the latter stacked in either sequence, are atomic layer deposited on r-cut alpha-Al2O3(0 1 (1) over bar 2) substrates. Thickness of the layers is varied. Epitaxial quality of the films is characterized by X-ray diffraction (XRD), reflection high-energy electron diffraction, and transmission electron microscopy. In gas response measurements, as-grown films and the films coated with electron-beam evaporated Pt nanoclusters are exposed, at 350 degrees C, to H-2, CO, and CH4 diluted in air. In response to test gas concentrations of 30 parts per million (ppm), the films with a thickness of order of 10 nm exhibit, depending on the makeup and gas, as high as two- to five-fold decrease in the resistance. It is shown that the platinum surface catalyst is effective in accelerating the response and recovery processes. The transition times of the order of a few tens of seconds are observed. The results demonstrate the feasibility of gas sensing with single-crystal-like nanolayer films. Comparison of sensor characteristics of such quasi-2D nanostructures and the literature data relevant to individual nanowires, nanorods, and nanobelts, i.e., typical representatives of the quasi-1D structures, shows that, as to H-2, CO, and CH4, both structures are worthy competitors.
27.	Schmera, Gabor, et al. (författare) Separating Chemical Signals of Adsorption-Desorption and Diffusive Processes 2010 Ingår i: IEEE Sensors Journal. - 1530-437X .- 1558-1748. ; 10:3, s. 461-464 Tidskriftsartikel (refereegranskat)abstract We present a new sensor signal processing method that improves selectivity, sensitivity, and processing speed in systems, using fluctuation-enhanced sensing. We consider the output signal of a symmetric two-sensor arrangement and generate two independent output spectra by separating the adsorption-desorption signal component from the diffusion signal component. We demonstrate the key features of our method by computer modeling and simulation.
28.	Shahzad, Khurram, et al. (författare) Architecture exploration for a high-performance and low-power wireless vibration analyzer 2013 Ingår i: IEEE Sensors Journal. - 1530-437X .- 1558-1748. ; 13:2, s. 670-682 Tidskriftsartikel (refereegranskat)abstract Vibration based condition monitoring is considered to be the most effective method for analyzing the performance of rotating machinery and for early fault detection. Traditional vibration analyzers used for this purpose provide wired interface(s) to connect sensors with the system that analyzes the vibration data. A wireless vibration analyzer can be useful to monitor and analyze the vibration of rotating as well as inaccessible parts of the machinery. However, for a wireless vibration analyzer, both the performance and power consumption are of major concern, especially for real-time tri-axes (horizontal, vertical, and axial) vibration data processing and analyses at a high sampling rate. To evaluate the performance of such an analyzer, we explore different architectures in order to realize a high-performance and low-power wireless vibration analyzer that can be used in addition to traditional analyzers. For this purpose, four different architectures have been implemented in order to evaluate them in terms of performance, power consumption, cost, and design complexity.
29.	Sieber, Arne, et al. (författare) Smart electrochemical oxygen sensor for personal protective equipment 2012 Ingår i: IEEE Sensors Journal. - 1558-1748 .- 1530-437X. ; 12:6, s. 1846-1852 Tidskriftsartikel (refereegranskat)abstract Self contained closed circuit rebreathers are life supporting breathing systems, where the exhaled gas is recycled by filtering CO2 and replacing metabolized O-2. For the O-2 injection control galvanic O-2 sensors are used to measure the partial pressure of O-2. A malfunction of the sensors can lead to a gas mixture beyond life supporting limits which is life threatening. Galvanic O-2 sensors are often used in anaesthetic machines in hospitals. Also in this case, a malfunction of the sensors can cause severe injury to a person. It is obvious that such sensors are key elements in life supporting equipment and as such must be designed in order to achieve high functional safety. However these sensors are consuming sensors, and with that, will fail at a certain time. Failure modes include current limitation, non linearity, electrolyte evaporation or leakage, etc. Within this paper a novel low cost read out electronic circuit for galvanic O-2 sensors is presented, which allows not only digital readout, digital temperature compensation, on board storage of calibration and manufacturing data, but also can be used for performing voltammetry cycles to test the Pb anode for exhaustion. First measurements are presented and compared to data from a Solartron SI 1287 impedance analyzer, which is state-of-the-art in electrochemical sensor characterization.
30.	Unander, Tomas, et al. (författare) Designing of RFID based Sensor Solution for Packaging Surveillance Applications 2011 Ingår i: IEEE Sensors Journal. - 1530-437X .- 1558-1748. ; 11:11, s. 3009-3018 Tidskriftsartikel (refereegranskat)abstract In this work, a two-chip battery assisted Radio Frequency Identification (RFID) based sensor platform is presented. The radio frequency communication interface is based on the EPC Gen 2 standard. A laboratory setup of the platform has been shown and characterized for a moisture content sensor application. The laboratory setup of the sensor platform has a reading range of 3.4 meters which is in comparison to commercial available Gen 2 tags. The laboratory platform has an average power consumption of 2.1 μW operating at 3 V, which together with a printed battery gives an estimated lifetime for data logging of several years. The proposed RFID platform provides a tradeoff between, communication performance, compatibility with international standards, and flexibility in on-package customization including type and number of sensors. The proposed architecture separates the high-performance communication circuit and the low-frequency sensor interface logic. In the future, the sensor interface maybe integrated using printed logics to further enhance the flexibility and low-ost customization features of the architecture
31.	Viter, Roman, et al. (författare) Application of Room Temperature Photoluminescence from ZnO Nanorods for Salmonella Detection 2014 Ingår i: IEEE Sensors Journal. - : Institute of Electrical and Electronics Engineers (IEEE). - 1530-437X .- 1558-1748. ; 14:6, s. 2028-2034 Tidskriftsartikel (refereegranskat)abstract ZnO nanorods grown by gaseous-disperse synthesis are confirmed by XRD analysis to have the wurtzite crystal structure. The obtained crystallites, as found from SEM studies, are 57 +/- 9 nm in diameter and 470 +/- 30 nm long on the average. Two emission bands of photoluminescence from ZnO nanorods observed at room temperature are centered at 376 and 520 nm. A biosensitive layer is prepared by immobilization of anti-Salmonella antibodies from liquid solutions on the ZnO surface. Immobilization of the biosensitive layer onto ZnO nanorods is found to increase the intensity of PL. After further reaction with Salmonella antigens (Ags), the PL intensity is found to decrease proportional to Ag concentrations in the range of 10(2)-10(5) cell/ml. The possible mechanism of biosensor response is suggested and discussed.
32.	Xie, Li, et al. (författare) Integration of f-MWCNT Sensor and Printed Circuits on Paper Substrate 2013 Ingår i: IEEE Sensors Journal. - 1530-437X .- 1558-1748. ; 13:10, s. 3948-3956 Tidskriftsartikel (refereegranskat)abstract The integration of sensors endows the packages with intelligence and interactivity. This paper is considered the most suitable substrate of smart packages because it is cost-effective, light, flexible, and recyclable. However, common concern exists regarding the reliability of paper-based system against bending and folding. In this paper, inkjet-printing of silver nanoparticles is used to form circuit pattern as well as interconnections for system integration on paper substrate. A humidity sensor made by functionalized multiwalled carbon nanotubes is fabricated on the same substrate. We evaluate the electrical performance of paper electronics and the reliability against bending and folding. The results reveal the capability and the limitation of paper electronics in terms of flexibility. The concept of a paper-based smart electronic system and the manufacture process are demonstrated by an interactive humidity sensor card prototype.
33.	Zhong, Jianghua, et al. (författare) Camera Control in Multi-Camera Systems for Video Quality Enhancement 2014 Ingår i: IEEE Sensors Journal. - 1530-437X .- 1558-1748. ; 14:9, s. 2955-2966 Tidskriftsartikel (refereegranskat)abstract Multiview video captured by multi-camera systems has been widely used in many applications such as surveillance, 3D television, and free viewpoint television. After capturing, the multi-camera system generally requires to compress a large amount of multiview data due to limitations on the transmission capacity. To improve video quality, previous work on video compression focused on algorithm refinements when a raw multiview video is compressed at a limited bit-rate, whereas existing work on instrumentation generally introduced higher resolution capture and additional hardware. In contrast, this paper uses camera control to enhance video quality. Individual cameras are controlled to adjust their pan angles and focal lengths to compensate for both object location difference and color inconsistency among camera views at the video acquisition stage. Such a compensation makes the camera images more similar and therefore improves the video quality when a raw multiview video is compressed at a limited bit-rate. The optimal pan angle and focal length are designed for each camera. An example application is to monitor a potted plant in real time for ornamental horticulture study. Experimental results validate the camera control method.
34.	Zhu, Jing-Jing, et al. (författare) Fiber-Optic High-Temperature Sensor Based on Thin-Core Fiber Modal Interferometer 2010 Ingår i: IEEE Sensors Journal. - 1530-437X .- 1558-1748. ; 10:9, s. 1415-1418 Tidskriftsartikel (refereegranskat)abstract We present a new fiber-optic high-temperature sensor based on a thin-core fiber (TCF) modal interferometer. A thin-core fiber, whose core radius is about half of the radius of a standard single-mode fiber (SMF), is inserted between standard SMFs to form an extremely simple in-fiber modal interferometer. The wavelength of the transmission dip increases linearly with the temperature. Experimental demonstration shows that it can be used to sense temperature up to 850 degrees C with a sensitivity of about 18.3 pm/degrees C.

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