| 1. |
- Scotti, S., et al.
(författare)
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Automatic quantitative evaluation of emotions in E-learning applications
- 2006
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Ingår i: Annu Int Conf IEEE Eng Med Biol Proc. - 1424400325 - 9781424400324 ; , s. 1359-1362
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Konferensbidrag (refereegranskat)abstract
- The long term goal of our research is to develop a tool for recognizing human emotions during e-learning processes. This could be accomplished by combining quantitative indexes extracted from non-invasive recordings of four physiological signals: namely skin conductance, blood volume pulse, electrocardiogram and electroencephalogram. Wearable, non-invasive sensors, communicating with a PC, were applied to 30 students and data were collected during exposure to three different computer-mediated content stimuli designed to evoke specific emotional states: stress, relaxation and engagement. In this paper we describe both the general emotion evaluation algorithm, and present a preliminary results suggesting that some of the quantitative indexes may be successful in characterizing and distinguishing between the three different emotional states.
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| 2. |
- Seoane, Fernando, 1976-, et al.
(författare)
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Current Source for Multifrequency Broadband Electrical Bioimpedance Spectroscopy Systems : A Novel Approach
- 2006
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Ingår i: 2006 28th Annual International Conference of the IEEE Engineering in Medicine and Biology Society, Vols 1-15. - 1424400325 - 9781424400324 ; , s. 5121-5125
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Konferensbidrag (refereegranskat)abstract
- New research and clinical applications of broadband electrical bioimpedance spectroscopy arise; increasing the upper limit frequency used in the measurement systems. The current source, an essential block of an electrical bioimpedance impedance analyzer, must have a large-enough output impedance at any frequency of operation to keep the output current constant regardless of the value of working load. In this paper a novel approach to increase the output impedance of a common voltage controlled current source is proposed. The circuit is analyzed, implemented and tested. The results, remarking the significant effect of the circuit parasitic capacitances, show a clear increment of the output impedance, but smaller than the originally expected
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| 3. |
- Hill, Andrew, et al.
(författare)
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Dynamic breast MRI: Image registration and its impact on enhancement curve estimation
- 2006
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Ingår i: Proc. 2006 Annual International Conference of the IEEE Engineering in Medicine and Biology Society. - 1424400325 ; , s. 3049 - 3052
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Konferensbidrag (refereegranskat)abstract
- A novel algorithm for performing registration of dynamic contrast-enhanced (DCE) MRI data of the breast is presented. It is based on an algorithm known as iterated dynamic programming originally devised to solve the stereo matching problem. Using artificially distorted DCE-MRI breast images it is shown that the proposed algorithm is able to correct for movement and distortions over a larger range than is likely to occur during routine clinical examination. In addition, using a clinical DCE-MRI data set with an expertly labeled suspicious region, it is shown that the proposed algorithm significantly reduces the variability of the enhancement curves at the pixel level yielding more pronounced uptake and washout phases
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| 4. |
- Löfhede, Johan, 1978, et al.
(författare)
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Detection of bursts in the EEG of post asphyctic newborns
- 2006
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Ingår i: 2006 28th Annual International Conference of the IEEE Engineering in Medicine and Biology Society. - 1557-170X. - 9781424400324 ; , s. 2179-2182, s. 5-6
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Konferensbidrag (refereegranskat)abstract
- Eight features inherent in the electroencephalogram (EEG) have been extracted and evaluated with respect to their ability to distinguish bursts from suppression in burst-suppression EEG. The study is based on EEG from six full term infants who had suffered from lack of oxygen during birth. The features were used as input in a neural network, which was trained on reference data segmented by an experienced electroencephalographer. The performance was then evaluated on validation data for each feature separately and in combinations. The results show that there are significant variations in the type of activity found in burst-suppression EEG from different subjects, and that while one or a few features seem to be sufficient for most patients in this group, some cases require specific combinations of features for good detection to be possible.
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| 5. |
- Sandberg, Frida, et al.
(författare)
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Frequency tracking of atrial fibrillation using hidden Markov models
- 2006
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Ingår i: IEEE Press. - 1557-170X. - 1424400325 ; , s. 1406-1409
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Konferensbidrag (refereegranskat)abstract
- A Hidden Markov Model (HMM) is used to improve the robustness to noise when tracking the atrial fibrillation (AF) frequency in the ECG. Each frequency interval corresponds to a state in the HMM. Following QRST cancellation, a sequence of observed states is obtained from the residual ECG, using the short time Fourier transform. Based on the observed state sequence, the Viterbi algorithm, which uses a state transition matrix, an observation matrix and an initial state vector, is employed to obtain the optimal state sequence. The state transition matrix incorporates knowledge of intrinsic AF characteristics, e.g., frequency variability, while the observation matrix incorporates knowledge of the frequency estimation method and SNRs. An evaluation is performed using simulated AF signals where noise obtained from ECG recordings have been added at different SNR. The results show that the use of HMM considerably reduces the average RMS error associated with the frequency tracking: at 5 dB SNR the RMS error drops from 1.2 Hz to 0.2 Hz.
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| 6. |
- Tohnak, Sirilawan, et al.
(författare)
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Synthesizing panoramic radiographs by unwrapping dental CT data
- 2006
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Ingår i: Proc. 2006 Annual International Conference of the IEEE Engineering in Medicine and Biology Society. - 1424400325 ; , s. 3329 - 3332
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Konferensbidrag (refereegranskat)abstract
- A method for synthesizing panoramic radiographs from dental CT data is presented. The method is based on the principles of panoramic radiography with a continuously-moving rotation center. The method computes discrete pixel sums through the CT data along normals to the medial axis of the dental arch. Compared to a conventional panoramic radiograph, the method produces less geometric distortion, less blurring, and less superimposition of other structures. The method is particularly suited to forensic identification of human remains in cases where the state of degradation precludes the possibility of obtaining a conventional panoramic radiograph
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