The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
Over 90% enhancement of efficient Cr4+ emission in Ca, Cr:YAG doubled-clad crystal fiber is achieved by CaO perimeter deposition, followed by oxygen annealing treatment. The corresponding strain effects on the Cr4+ broadband emission are also discussed.
Modern localization systems/platforms such as sensor networks often experience uncertainty in the sensor positions. Improving the sensor positions is necessary in order to achieve better localization performance. This paper proposes a joint estimator for locating multiple unknown sources and refining the sensor positions using TOA measurements. Rather than resorting to the traditional iterative nonlinear...
Nanopatterning using near-field optics has shown great potential for industrial applications. A novel application of water droplets to this technology is proposed in this study. With a hydrophobic layer and controlled substrate temperature, a layer of randomly distributed water droplets with a high contact angle is formed on the substrate. These liquid droplets can be used as lenses to enhance the...
Shifts in technological paradigms simultaneously disrupt existing industrial organization and raise opportunities for entrepreneurial companies. Analyzing the process of paradigm shift requires a systematic framework involves a variety of factors related to market conditions, industrial organization, and the broader technical environment. This research develops a typology as an analytical framework...
The problem of determining the position of a sound source using mobile devices such as smart phones is considered in this paper. A novel calibration stage is developed to cancel out the time offsets of the time differences of arrival measurements. Two localization algorithms, one closed-form solution and the other iterative approach, are implemented to examine the performance of the proposed sound...
The Frequency Response Analysis (FRA) is considered as an useful measure to detect deformation and changes of the active part of transformers. However, the corresponding interpretation is still subject of different investigation as there are many questions to be answered.
The lumped transformer equivalent circuit has been recently adapted based on duality principle and verified for the purposes of transient analysis with reasonable accuracy and frequency response analysis. However such circuit is developed and validated for balanced and unbalanced three-phase excitation. On the other hand, several diagnostic tests such as Frequency Response Analysis (FRA), ratio, short-circuit...
Automatic License Plate Recognition (ALPR) can avoid faults of manual license plate recognition, like pressing keys wrongly or too slowly. But, there are inevitably some vertical and horizontal perspective distortions between the license plates and ALPR's cameras, degrading the accuracy and reliability of ALPR significantly. This paper proposes a Homography-based perspective correction method for...
Falling is a common health problem for more than a third of the United States population over 65. We are currently developing a Doppler radar based fall detection system that already has showed promising results. In this paper, we study the sensor positioning in the environment with respect to the subject. We investigate three sensor positions, floor, wall and ceiling of the room, in two experimental...
Falls represent an important health problem for older adults. This issue continues to generate interest in the research and development of fall detection systems. In previous work we proposed an acoustic fall detection system (acoustic-FADE) that employs an 8-microphone circular array to automatically detect falls. Acoustic-FADE has achieved encouraging results: 100% detection at 3% false alarm rate...
This paper investigates bias compensation for improving the performance of target tracking using range or range difference measurements. We obtain the Maximum Likelihood estimate of the target position at the current instant and pass it to the Kalman filter as observation to obtain the target track. The nonlinear relationship between the target position and measurements creates bias that can degrade...
The nonlinear nature of the source localization problem creates bias to a location estimate. The bias could play a significant role in limiting the performance of localization and tracking when multiple measurements at different instants are available. This paper performs bias analysis of the source location estimate obtained by the maximum likelihood estimator, where the positioning measurements...
Strofio is a scientific investigation to sample in-situ the neutral atoms in Mercury's exosphere. Strofio is based on a novel mass spectrograph that determines the particle mass-per-charge (m/q) by a time-of-flight (TOF) technique. This novel technique achieves a mass resolution (m/Δm) at mass 18 of >100, with a high sensitivity of 0.14 (counts/s)/(particles/cm3) and a mass of only 4kg. Strofio...
ICU patients are vulnerable to in-ICU morbidities and mortality, making accurate systems for identifying at-risk patients a necessity for improving clinical care. Here, we present an improved model for predicting in-hospital mortality using data collected from the first 48 hours of a patient's ICU stay. We generated predictive features for each patient using demographic data, the number of observations...
This paper considers the problem of sliding mode control (SMC) for a class of linear uncertain switched systems. In the controlled systems, it is not required that each subsystem model shares the same input channel, which is usually assumed in some existing works. By means of a transformation on input matrices, a single integral sliding surface is designed and the switching signals depending on the...
This work develops a pair of mobile payment devices, a counter reader and a paying client, on Android-based smartphone platforms for emerging mobile payment or electronic wallet services. These two devices featuring 3-factor authentication and virtual private Ad Hoc networking can make an easier and securer transaction than traditional credit cards or electronic payment cards. 3-factor authentication...
Shift in technological paradigm usually brings critical impacts to existing products, companies and societies. Although the Schumpeterian economists have well discussed the destructive impact of technological change of this type, systematic analysis of paradigmatic change in technology surely help technology managers in allocating research resources. This study develops an analytical model based on...
The application of energy scavenging technology significantly improves wireless sensor network nodes long-term operation and ensures minimal user attendance. For most of the scavenging technologies, ambient energy is available only under particular environmental conditions. For this reason, wireless sensor nodes have to keep the scavenged energy in storage elements. In this paper we present a kind...
This paper is concerned with the ℋ∞ dynamic output feedback (DOF) control problem for discrete-time switched Itô stochastic hybrid systems. By applying the average dwell time method and the piecewise Lyapunov function technique, a sufficient condition is first proposed, which guarantees the closed-loop switched stochastic system to be mean-square exponentially stable with a weighted ℋ∞ performance...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.