Detection of seizures from small samples using nonlinear dynamicsystem theory

The electroencephalogram (EEG), like many other biological phenomena, is quite likely governed by nonlinear dynamics. Certain characteristics of the underlying dynamics have recently been quantified by computing the correlation dimensions (D₂) of EEG time series data. In this paper, D₂ of the unbiased autocovariance function of the scalp EEG data was used to detect electrographic seizure activity. Digital EEG data were acquired at a sampling rate of 200 Hz per channel and organized in continuous frames (duration 2.56 s, 512 data points). To increase the reliability of D₂ computations with short duration data, raw EEG data were initially simplified using unbiased autocovariance analysis to highlight the periodic activity that is present during seizures. The D₂ computation was then performed from the unbiased autocovariance function of each channel using the Grassberger-Procaccia method with Theiler's box-assisted correlation algorithm. Even with short duration data, this preprocessing proved to be computationally robust and displayed no significant sensitivity to implementation details such as the choices of embedding dimension and box size. The system successfully identified various types of seizures in clinical studies     

Telepresence feedback and input systems for a twin armed mobilerobot

Complex tasks in unstructured/hazardous environments often require teleoperation. The telepresence robot featured here has “user friendly” limb linked output and feedback systems. The mechanism design and sensory feedback of visual, audio and multi-functional tactile (pressure, texture/slip and thermal parameters) are described     

Neural Models for the Resonant Frequency of Electrically Thin and Thick Circular Microstrip Antennas and the Characteristic Parameters of Asymmetric Coplanar Waveguides Backed with a Conductor

Neural models for computing the resonant frequency of electrically thin and thick circular microstrip antennas, based on the multilayered perceptrons and the radial basis function networks, are presented. Five learning algorithms, delta-bar-delta, extended delta-bar-delta, quick-propagation, directed random search and genetic algorithms, are used to train the multilayered perceptrons. The radial basis function network is trained according to its learning strategy. The resonant frequency results of neural models are in very good agreement with the experimental results available in the literature. In this paper, the characteristic impedance and the effective permittivity of the asymmetric coplanar waveguide backed with a conductor are also computed by using only one neural model trained by the backpropagation with momentum and the extended delta-bar-delta algorithms. When the performances of neural models are compared with each other, the best results for test are obtained from the multilayered perceptrons trained by the extended delta-bar-delta algorithm.     

Fuzzy logic-based performance improvement on MAC layer in wireless local area networks

There are many studies that have been done to improve the quality of service of wireless local area networks (WLANs). Institute of Electrical and Electronic Engineers (IEEE) WLAN are based on IEEE 802.11 protocol. The 802.11e medium access control (MAC) protocol is generally recommended for efficient quality of service in WLANs. There are many parameters in the MAC protocol that affect quality of services. Among these parameters, request to send threshold value (RSTV), fragmentation threshold value (FTV) and buffer size (BS) directly affect network performance. RSTV is used in the request to send/clear to send (RTS/CTS) mechanism in the carrier sense multiple access with collision avoidance (CSMA/CA) protocol for collision prevention. This parameter specifies the threshold used to activate the CSMA/CA protocol. FTV is another parameter that is used to send large-sized packets by dividing them into appropriate fragments during CSMA/CA transmission and reduces packet loss in WLAN. BS is another parameter that has a significant cost in the CSMA/CA model and also directly affects the performance. In this article, to improve the performance of WLANs, OPNET Modeler was used and ideal values were obtained for RSTV, FTV and BS by using fuzzy logic-based method. The values obtained by fuzzy logic were re-tested in OPNET Modeler, and the achieved improvement was as follows: for delay 36–38%, for load 2–10% and for throughput 25–44%, respectively. Thus, in WLANs, performance was improved by using fuzzy logic-based method.

     

Area-based results for mine detection

The cost and the closely related length of time spent in searching for mines or unexploded ordnance (UXO) may well be largely determined by the number of false alarms. False alarms can result in time consuming digging of soil or in additional multisensory tests in the minefield. The authors consider two area-based methods for reducing false alarms. These are: (a) the previously known “declaration” technique and (b) the new δ technique, which they introduce. They first derive expressions and lower bounds for false-alarm probabilities as a function of declaration area and discuss their impact on receiver operation characteristic (ROC) curves. Second, they exploit characteristics of the statistical distribution of sensory energy in the immediate neighborhood of targets and of false alarms from available calibrated data, to propose the δ technique, which significantly improves discrimination between targets and false alarms. The results are abundantly illustrated with statistical data and ROC curves using electromagnetic-induction sensor data made available through DARPA from measurements at various calibrated sites     

Magnetic Properties of Zn1?x Ni x O (0.25≤x≤ 0.50) Prepared by Solid-State Reactions

In this study the origin of ferromagnetism in ZnO-based bulk systems has been investigated using Ni-doped ZnO samples, Zn_1−x Ni _x O with 0.25≤x≤0.50, prepared by solid-state reactions. The structural characterizations indicated that the Ni²⁺ ions almost uniformly distributed in all the samples, and the samples have hexagonal wurtzite structure; however, when x is increased toward 0.50, a new NiO phase is formed. A ferromagnetism (FM) has been observed for all the samples at and below the room temperature. In other words, the room temperature results of (M–H) curves show that the FM observed is intrinsic for all the Ni-doped ZnO samples. However, the saturated magnetizations decrease gradually with increasing Ni concentration. This indicates that, in addition to FM, the excessive doping of Ni in ZnO also causes an antiferromagnetic (AFM) contribution which increases with increasing Ni amount. This result is also supported by the magnetization against temperature measurements. Furthermore, the trend of the ac-susceptibility (χ) versus temperature curves, measured under an ac-magnetic field of 100 Oe, also support our conclusion about the antiferromagnetic contribution to ferromagnetism in our samples.     

Bonding performance of universal adhesives to er,cr:YSGG laser‐irradiated enamel

Universal adhesives have been recently introduced for use as self‐etch or etch‐and‐rinse adhesives depending on the dental substrate and clinical condition. However, their bonding effectiveness to laser‐irradiated enamel is still not well‐known. Thus, the aim of this study was to compare the shear bond strength (SBS) of universal adhesives (Single Bond Universal; Nova Compo‐B Plus) applied to Er,Cr:YSGG laser‐irradiated enamel with SBS of the same adhesives applied in self‐etch and acid‐etching modes, respectively. Crown segments of sixty bovine incisors were embedded into standardized acrylic blocks. Flattened enamel surfaces were prepared. Specimens were divided into six groups according to universal adhesives and application modes randomly (n = 10), as follows: Single Bond Universal/acid‐etching mode; Nova Compo‐B Plus/acid‐etching mode; Single Bond Universal/self‐etching mode; Nova Compo‐B Plus/self‐etching mode; and Single Bond Universal/Er,Cr:YSGG Laser‐etching mode; Nova Compo‐B Plus/Er,Cr:YSGG Laser‐etching mode. After surface treatments, universal adhesives were applied onto surfaces. SBS was determined after storage in water for 24 h using a universal testing machine with a crosshead speed of 0.5 mm min^?1. Failure modes were evaluated using a stereomicroscope. Data was analyzed using two‐way of analyses of variances (ANOVA) (p = 0.05). Two‐way ANOVA revealed that adhesive had no effect on SBS (p = 0.88), but application mode significantly influenced SBS (p = 0.00). Acid‐etching significantly increased SBS, whereas there are no significant differences between self‐etch mode and laser‐etching for both adhesives. The bond strength of universal adhesives may depend on application mode. Acid etching may significantly increase bond strength, while laser etching may provide similar bond strength when compared to self‐etch mode.     

Comparison of four different heuristic optimization algorithms for the inverse kinematics solution of a real 4-DOF serial robot manipulator

In this study, a 4-degree-of-freedom (DOF) serial robot manipulator was designed and developed for the pick-and-place operation of a flexible manufacturing system. The solution of the inverse kinematics equation, one of the most important parts of the control process of the manipulator, was obtained by using four different optimization algorithms: the genetic algorithm (GA), the particle swarm optimization (PSO) algorithm, the quantum particle swarm optimization (QPSO) algorithm and the gravitational search algorithm (GSA). These algorithms were tested with two different scenarios for the motion of the manipulator’s end-effector. One hundred randomly selected workspace points were defined for the first scenario, while a spline trajectory, also composed of one hundred workspace points, was used for the second. The optimization algorithms were used for solving of the inverse kinematics of the manipulator in order to successfully move the end-effector to these workspace points. The four algorithms were compared according to the execution time, the end-effector position error and the required number of generations. The results showed that the QPSO could be effectively used for the inverse kinematics solution of the developed manipulator.