Current Sensor Technology Research Articles

Local Information Access for Search and Rescue Using Wireless Data Storage Mediums

After a natural disaster strikes buildings, it is vital to immediately retrieve the related local information for efficient search and rescue (S&R) operations. Although it seems convenient to store the required local information (e.g., information about neighborhood, buildings) in a centralized database, S&R teams usually cannot access centralized databases because the information infrastructure is usually damaged or overloaded immediately after a disaster. This paper describes the search and rescue data access point (SR-DAP) system that was designed for storing and retrieving the required local information in/from data storage units that are deployed at buildings. In the paper, the developed approach is presented, and two key technologies (i.e., radio-frequency identification (RFID) tags and wireless sensor nodes) that are used as local storage mediums in SR-DAP are empirically evaluated. The results of the field experiments show that current technologies can be effectively utilized in the developed system. However, comparison of the technologies highlights the fact that the current wireless sensor technology is advantageous over RFID technology.

Satellite remote sensing of sea-ice thickness and kinematics: a review

AbstractObservations of sea-ice thickness and kinematics are essential for understanding changes in sea-ice mass balance, interactions between the ice cover and the ocean and atmosphere and for improving projections of sea-ice response in a warming climate. These parameters are not directly observable with current sensor technology, but are derived from satellite altimetry and imagery. While there is progress in the retrievals of Arctic sea-ice thickness from satellite altimetry, approaches to address Southern Ocean ice thickness require additional attention. On the other hand, procedures to derive sea-ice motion from satellite imagery are more mature and better understood and have been employed to produce useful results for more than a decade. Adequate sampling of sub-daily ice motion, however, remains a challenge. Generally, satellite instruments provide large-scale coverage but the frequency of temporal sampling is limited by orbit characteristics. In this review, I focus on the approaches, uncertainties, sampling limitations and validation issues associated with the estimation of sea-ice thickness and motion. I provide a summary of current and anticipated capabilities for monitoring sea-ice thickness and kinematics from space. The prospects for continuing these measurements into the next decade, from a satellite remote-sensing perspective, are discussed.

Safety in simultaneous ultra-low-field MRI and MEG: forces exerted on magnetizable objects by magnetic fields

Event Abstract Back to Event Safety in simultaneous ultra-low-field MRI and MEG: forces exerted on magnetizable objects by magnetic fields Juhani Dabek1*, Fredrik Sannholm1, Jaakko O. Nieminen1, Panu T. Vesanen1 and Risto J. Ilmoniemi1 1 Aalto University , Finland Magnetic resonance imaging (MRI) can be combined with magnetoencephalography (MEG) in one apparatus (MEG-MRI) to image the human brain. With the current sensor technology, to record the weak biomagnetic signals in MEG-MRI, the MRI sequences are carried out in ultra-low fields, typically in the microtesla regime. On the other hand, in order to guarantee sufficient MR image quality, the sample is prepolarized in a higher magnetic field. Ultra-low-field MRI is generally safe, but, the prepolarization field, although much weaker than the main field in high-field MRI, must be considered for safe operation of the apparatus. It can be shown that for a non-saturated, linearly magnetizable object, the magnetic force on it is directly proportional to the product of the strength of the magnetic field and that of its gradient. On the other hand, the phenomenon of demagnetization causes the force to be weaker on flat objects compared to elongated objects. This has been confirmed by our experiments on the symmetry axis of a Helmholtz coil. These effects need to be considered when the subject to be imaged has, e.g., medical implants or surgical clips. Other prominent risks associated with MRI experiments relate to rapidly switched magnetic fields or their gradients (peripheral nerve stimulation), the possible use of RF pulses (specific absorption rate) and cryogenics (sudden quench). The risks with the magnetic forces on magnetizable objects could result in projectile danger or tissue damage, and need careful study. Important aspects with respect to the potentially affected objects are, e.g., their composition, shape and electrical properties. Eventually, it is proposed that families of metallic objects close to the MEG-MRI apparatus, external or internal to the subject, should be validated for safety with respect to the magnetic forces due to the prepolarization field. Conference: Biomag 2010 - 17th International Conference on Biomagnetism , Dubrovnik, Croatia, 28 Mar - 1 Apr, 2010. Presentation Type: Poster Presentation Topic: Instrumentation and Multi-modal Integrations: MEG, Low-field MRI,EEG, fMRI,TMS,NIRS Citation: Dabek J, Sannholm F, Nieminen JO, Vesanen PT and Ilmoniemi RJ (2010). Safety in simultaneous ultra-low-field MRI and MEG: forces exerted on magnetizable objects by magnetic fields. Front. Neurosci. Conference Abstract: Biomag 2010 - 17th International Conference on Biomagnetism . doi: 10.3389/conf.fnins.2010.06.00029 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 19 Mar 2010; Published Online: 19 Mar 2010. * Correspondence: Juhani Dabek, Aalto University, Espoo, Finland, juhani.dabek@tkk.fi Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Juhani Dabek Fredrik Sannholm Jaakko O Nieminen Panu T Vesanen Risto J Ilmoniemi Google Juhani Dabek Fredrik Sannholm Jaakko O Nieminen Panu T Vesanen Risto J Ilmoniemi Google Scholar Juhani Dabek Fredrik Sannholm Jaakko O Nieminen Panu T Vesanen Risto J Ilmoniemi PubMed Juhani Dabek Fredrik Sannholm Jaakko O Nieminen Panu T Vesanen Risto J Ilmoniemi Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Antibody-based biosensors for environmental monitoring

Antibody-based biosensors provide sensitive and rapid analytical tools for the detection of a range of pathogens and associated toxins. In this paper, the recent progress in antibody-based biosensors for environmental monitoring is reviewed with particular emphasis on generation and immobilization methods of antibody capture probes. We also describe the current available data on antibody-based detection of pathogens and toxins. Optimal assay design and the strengths and limitations of current sensor technologies for detection of biological agents in environment on site are also discussed.

SEVA

In this article, we study how a sensor-rich world can be exploited by digital recording devices such as cameras and camcorders to improve a user's ability to search through a large repository of image and video files. We design and implement a digital recording system that records identities and locations of objects (as advertised by their sensors) along with visual images (as recorded by a camera). The process, which we refer to as Sensor-Enhanced Video Annotation (SEVA) , combines a series of correlation, interpolation, and extrapolation techniques. It produces a tagged stream that later can be used to efficiently search for videos or frames containing particular objects or people. We present detailed experiments with a prototype of our system using both stationary and mobile objects as well as GPS and ultrasound. Our experiments show that: (i) SEVA has zero error rates for static objects, except very close to the boundary of the viewable area; (ii) for moving objects or a moving camera, SEVA only misses objects leaving or entering the viewable area by 1--2 frames; (iii) SEVA can scale to 10 fast-moving objects using current sensor technology; and (iv) SEVA runs online using relatively inexpensive hardware.

Development and Applications of Continuous-Wave Cavity Ring-Down Spectroscopy

Continuous-wave cavity ring-down spectroscopy (CW-CRDS) (using continuous-wave lasers) is now in widespread use for the sensitive detection of a range of different trace-gas species, including water vapor as a very important trace contaminant in many gases. It has also now been applied to monitor trace water vapor in a range of matrix gases, including those that are corrosive and have the potential for spectral interference with the target water-vapor species. The developments that have been carried out to achieve this will be discussed, and some of the applications, covering single sensors and multi-head sensors, will be presented. One limitation of the current sensor technology is that it uses mirrors that are highly reflective over a very restricted spectral range, and this limits a given sensor to the measurement of one or two gaseous species. Measurements of other species require the mirrors to be changed, as it is not currently practical to obtain mirrors with the required high reflectivity that also cover a large spectral range. The development of a new type of ring-down cavity that uses uncoated reflective optics, and which can be used from the ultraviolet to the infrared spectral regions, is presented. Examples of industrial and scientific applications are also presented.

ESTIMATION OF BIOMASS CONCENTRATION USING INTERVAL OBSERVERS IN AN E. COLI FED-BATCH FERMENTATION

In bioreactors, the measurement of variables that play a key role in the quality and productivity of fermentations, is of major importance. However, their direct measurement is often expensive or even impossible considering the current sensor technology. Therefore, on-line estimation of unmeasured variables in bioreactors can be an interesting approach. The objective of this work is to introduce an alternative solution for the observation of biomass concentration in E. coli fed-batch fermentations, in cases where the kinetic model is unclear and several variables, like the concentration of the influent substrates and the initial values of the state variables are badly known, a situation that is common in many practical applications. The simple interval observer is designed on the basis of the cooperativity properties of the observer error dynamics (Rapaport and Dochain, 2005). The performance of the interval observer is illustrated through numerical simulation and it was found that the observer deal well with uncertainties up to 50% and with white noise in the variables measured on-line. The interval obtained for the biomass estimation is also quite narrow, indicating that it is possible to accurately predict biomass concentration under the presence of uncertainties.

Autonomous welding of large steel fabrications

PurposeDevelopment and demonstration of an autonomous, mobile welding robot capable of fabricating large‐scale customised structures.Design/methodology/approachAn autonomous welding robot has been developed under the EC Framework V Growth program. The system comprises a global vision system for part location and orientation, and a robot transport vehicle (RTV) which carries a 6‐axis robot, robot controller, welding equipment, and local sensors at the welding torch. The RTV path, robot arm motion and weld process programming are performed automatically using sensors and specially customised simulation software.FindingsThe technology developed within the project was demonstrated, in November 2004, to be capable of identifying and welding large scale customised structures as found in the earth moving equipment and bridge fabrication industries.Research limitations/implicationsThe project demonstrated that current sensor technology is capable of being applied successfully to autonomous robots, but further developments in sensor technology are required to improve accuracy and joint access.Practical implicationsThe NOMAD concept of autonomous mobile robots provides an alternative solution to welding mass customised structures.Originality/valueThis project demonstrated, for the first time, the capability of autonomous robots to weld large scale customised structures.

Current Status of Hybrid Bearing Damage Detection

Advances in material development and processing have led to the introduction of ceramic hybrid bearings for many applications. The introduction of silicon nitride hybrid bearings into the high-pressure oxidizer turbopump on the space shuttle main engine led NASA to solve a highly persistent and troublesome bearing problem. Hybrid bearings consist of ceramic balls and steel races. The majority of hybrid bearings utilize Si3N4 balls. The aerospace industry is currently studying the use of hybrid bearings and, naturally, the failure modes of these bearings become an issue in light of the limited data available. In today's turbine engines and helicopter transmissions, the health of the bearings is detected by the properties of the debris found in the lubrication line when damage begins to occur. Current oil debris sensor technology relies on the magnetic properties of the debris to detect damage. Because the ceramic rolling elements of hybrid bearings have no metallic properties, a new sensing system must be developed to indicate the system health if ceramic components are to be safely implemented in aerospace applications. The ceramic oil debris sensor must be capable of detecting ceramic and metallic component damage with sufficient reliability and forewarning to prevent a catastrophic failure. The objective of this research is to provide a background summary on what is currently known about hybrid bearing failure modes and to report preliminary results on the detection of silicon nitride debris in oil using a commercial particle counter.

A Gas Sensor Array Using Carbon Nanotubes and Microfabrication Technology

Monitoring concentrations of chemicals, gases, and vapors is a critical task in the chemical industry, power plants, automotive exhaust, environmental protection, planetary science, and numerous other situations. Chemical sensors for specific species with varying sensitivity and discrimination levels are commercially available. Common chemical sensors differ in terms of the sensing material and the nature of the property change such as electrical conductivity, optical characteristics, temperature, etc.. Some of the current sensor technologies include high temperature oxide thin-film sensors, polymer-based sensors, catalytic-based sensors, and surface acoustic wave sensors. 1 Key attributes expected of a sensor include sensitivity in the parts per million to billion ppm, ppb range where trace levels are involved, absolute discrimination, room temperature operation, low power consumption, reasonable size, volume and mass, and low cost for large-scale applications. Given such a broad set of desirable attributes and diverse application fields, sensor development is a constantly evolving research area. The newest contributions to this field are nanoscience and technology where novel nanomaterials, because of their size, large surface to volume ratio, and properties that differ from their bulk counterparts, promise to offer better performance than micro- and macrosensors. Some of the candidate nanomaterials include carbon nanotubes CNTs, 2

Quantitative approach for damage detection of reinforced concrete frames

The objective of this paper is to provide an analytical basis for the quantitative evaluation of damage to a reinforced concrete structure based on the vibration data obtained by using the damage detection technique. A partial reinforced concrete system of a weak beam/strong column moment frame is chosen as an example. A pushover analysis is carried out in order to numerically examine both the story shear-relative displacement characteristics and the associated damage level. In the analysis, a two dimensional nonlinear finite element analysis is employed considering several constitutive models. As a result, the degradation of the stiffness at the damaged story is characterized in association with the story relative displacement. It is also pointed out that the rotation angle of the column-base is highly correlated with the story relative displacement. Based on the analytical findings, quantitative approaches for a structural health monitoring system are suggested considering both the current sensor technologies and those available in the future.

Vision-guided flight stability and control for micro air vehicles

Substantial progress has been made recently towards designing, building and test-flying remotely piloted micro air vehicles (MAVs) and small unmanned air vehicles. We seek to complement this progress in overcoming the aerodynamic obstacles to flight at very small scales with a visionguided flight stability and autonomy system, based on a robust horizon detection algorithm. In this paper, we first motivate the use of computer vision for MAV autonomy, arguing that given current sensor technology, vision may be the only practical approach to the problem. We then describe our statistical vision-based horizon detection algorithm, which has been demonstrated at 30 Hz with over 99.9% correct horizon identification. Next, we develop robust schemes for the detection of extreme MAV attitudes, where no horizon is visible, and for the detection of horizon estimation errors, due to external factors such as video transmission noise. Finally, we discuss our feedback controller for selfstabilized flight and report results on vision-based autonomous flights of duration exceeding 10 min. We conclude with an overview of our on-going and future MAV-related research.

Multisensor fusion and integration: approaches, applications, and future research directions

Multisensor fusion and integration is a rapidly evolving research area and requires interdisciplinary knowledge in control theory, signal processing, artificial intelligence, probability and statistics, etc. The advantages gained through the use of redundant, complementary, or more timely information in a system can provide more reliable and accurate information. This paper provides an overview of current sensor technologies and describes the paradigm of multisensor fusion and integration as well as fusion techniques at different fusion levels. Applications of multisensor fusion in robotics, biomedical system, equipment monitoring, remote sensing, and transportation system are also discussed. Finally, future research directions of multisensor fusion technology including microsensors, smart sensors, and adaptive fusion techniques are presented.

Radiometric standards in space: the next step

The lack of accurate calibration sources is preventing current sensor technology from achieving the minimum possible uncertainty levels in remote-sensing radiometric measurements. This has been established in a recent study undertaken at the National Institute of Standards and Technology (NIST) following the identification of the problem at the Calibration Source Requirements Workshop at the NIST in 1997. This paper presents the concept of establishing high-accuracy calibration sources in space, utilizing the International Space Station (ISS) as a platform. For example, a retrievable total solar irradiance radiometer standard could be deployed on the ISS in order to establish the Sun as a calibration source of the required accuracy. Periodic measurements of solar irradiance with this radiometer standard would help to establish the Sun as a radiometric standard with the accuracy needed for various radiometric sensors on other platforms in space. As the radiometer on the ISS would be retrievable, its traceability to the International System of Units (SI) could be maintained by periodically bringing it down for calibration with SI-traceable standards maintained in ground laboratories. Other suitable radiometric standards on the ISS could also establish the Moon, the stars and various ground sites as calibration sources.

A review of current sensor technologies and applications within automotive and traffic control systems

This paper reviews the current practice in sensors and sensor applications for automotive and traffic control systems. Sensors to control engine fuelling, ignition and transmission (known as the powertrain) are reviewed, and the likely course of future development is discussed in the light of regulatory and market requirements as well as trends in sensor design and manufacture. Sensor needs for suspension, braking and traction control are also reviewed, and the likely introduction of wheel and tyre sensors to enhance driving safety is discussed. The recent trend towards vehicle-mounted devices to sense the vehicle environment (such as radar, optical, ultrasound, capacitive and image-based systems) is discussed, and the sensor implications of the introduction of safety-critical automotive systems such as adaptive cruise control (ACC) are discussed. Sensors for initiating the deployment of safety systems such as airbags are reviewed, together with transducers for disconnecting fuel pumps and vehicle batteries in the event of a crash. The paper includes a brief discussion of highway-based sensors for measuring vehicle speed and presence, and concludes with a discussion of the likely future developments in the field.

Current Sensor Technology for Heart Rate Modulation by Artificial Pacing

Current Sensor Technology for Heart Rate Modulation by Artificial Pacing

Sliding Mode Fuel-Injection Controller: Its Advantages

New and improved results are presented on the advantages of employing the sliding mode control method for designing a closed-loop fuel-injection system. The two biggest advantages of this method are: (1) its compatibility with the current oxygen sensor technology and (2) its ability to consider robustness and performance issues analytically for an automotive engine, whose operating characteristics are highly complex and nonlinear. The controller can achieve the stoichiometric ratio control of air and fuel with excellent transient properties and is robust to model errors and disturbances. Furthermore, through direct comparisons to PI-controllers, it is shown that the sliding mode fuel-injection controller is versatile and requires very little tuning time. Performance evaluations are performed both on an engine-only model and on a comprehensive powertrain model that includes automatic transmission and drivetrain dynamics.

A new device to decrease falls

Falls are a serious health problem in old adults especially in nursing home residents and hospitalized patients. To prevent elderly from falling, sensors have been increasingly used in intramural care settings. However, there is no clear overview of the current used technologies and their results in fall prevention.The present study reviews sensor systems that prevent falls in geriatric patients living in an intramural setting and describe fall rates, fall-related injuries, false alarms, and user experience associated with such systems.We conducted a systematic search for studies that used sensor technologies with the aim to prevent falls in institutionalized geriatric patients.A total of 12 studies met the search criteria. Three randomized clinical trials reported no reductions in fall rate but three before–after studies reported significant reductions of 2.4–37 falls per 1000 patient days. Although there was up to 77% reduction in fall-related injuries and there was relatively low, 16%, rate of false alarms, the current data are inconsistent whether current sensor technologies are effective in reducing the number of falls in institutionalized geriatric patients. The occurrence of false alarms (16%) was too high to maintain full attention of the nursing staff. Additionally including the users opinion and demands in developing and introducing sensor systems into intramural care settings seems to be required to make an intervention successful.The evidence is inconsistent whether the current sensor systems can prevent falls and fall-related injuries in institutionalized elderly. Further research should focus more comprehensively on user requirements and effective ways using intelligent alarms.