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Review mode Essay CHAPTER 2 REVIEW OF RELATED LITERATURE AND STUDIES Studies rely on information researched by the proponents. Review of Related Literature In exploration, we find new techniques, new knowledge, even develop new substances, gadgets, equipment, processes or procedures, imagination and skill is emhapter II Review of Related Literature and Studies This chapter presents the literature and related studies which have direct bearing on this study. It also discusses the values reflected in the proverbs and the proverb as a reflection of Filipino character, its function in the society, its naReview of Related Literature and Studies CHAPTER 2 REVIEW OF RELATED LITERATURE AND STUDIES Studies rely on information researched by the proponents. Review of Related Literature In exploration, we find new techniques, new knowledge, even develop new substances, gadgets, equipment, processes or procedures, imagination and skill is em Premium1418 Words6 Pages Computer Effects on the Academic Performance of Students Review of Related Literature â€Å"Effects of computer usage to the academic performance of students† Chapter II REVIEW OF RELATED LITERATURE The scope of Computer effects derives a wide scope of related literature that is worth mentioning. In this regard, this literature review concerning the effects of computer usage Premium1010 Words5 Pages Chapter2: Review of Related Literature and Studies Chapter II Review of Related Literature and Studies This chapter presents the literature and related studies which have direct bearing on this study. It also discusses the values reflected in the proverbs and the proverb as a reflection of Filipino character, its function in the society, its na Premium1848 Words8 Pages Review of Related Literature Review of Related Literature History of Forums In the past, forums were viewed as places for geeks to communicate via the web. However, as the internet continues to grow and define itself, we have found them to be a very valuable resource of information. Forums benefit your internet experi Premium836 Words4 Pages Review of Related Literature REVIEW OF RELATED LITERATURE Background and Literature Overview The regulatory landscape of the air transport industry throughout the world has been changing dramatically since the 1980s to meet the growing density of air traffic as a result of the increasing integration of economies.

P300-based Brain-Computer Interface Performance Enhancement

P300-based Brain-Computer Interface Performance Enhancement Enhancing Performance and Bitrates in a P300-based Brain-Computer Interface for Disabled Subjects by Phase-to-Amplitude Cross-Frequency Coupling Stavros I.Dimitriadis1,2*, Avraam D. Marimpis3 1Institute of Psychological Medicine and Clinical Neurosciences, Cardiff University School of Medicine, Cardiff, UK 2Cardiff University Brain Research Imaging Center, School of Psychology, Cardiff University, Cardiff, UK 3Brain Innovation B.V., Netherlands Abstract A brain-computer interface (BCI) is a communication system that transforms brain-activity into specific commands for managing a computer or other home or electrical devices. In other words, a BCI is an alternative way of interacting with the environment by using brain-activity instead of muscles and nerves. For that reason, BCI systems are of high clinical value for targeted populations suffering from neurological disorders. In this paper, we present a new processing approach of a well-known P300-BCI system for disabled subjects. Estimating cross-frequency coupling (CFC) and namely ÃŽÂ ´-ÃŽÂ ¸ phase-to-amplitude coupling (PAC) within sensor, we succeeded high classification accuracy and high bitrates for both disabled and able-bodied subjects. The system is tested with four severely disabled and four able-bodied subjects. The bitrates obtained for both the disabled and able-bodied subjects reached the fastest reported level of 10 bits/sec. The new preprocessing approach based o n recordings from the single-sensor Pz while the classification accuracy is tested also for others electrodes. Keywords: Brain-computer interface; P300; Disabled subjects; cross-frequency coupling; accuracy *Corresponding author: Dr.Dimitriadis Stavros Research Fellow School of Medicine, Cardiff University, UK CUBRIC Neuroimaging Center, Cardiff,UK Introduction From the very first work of Farwell and Donchin [1] the majority of P300-based Brain Computer Interface (BCI) systems focused on developing new application scenarios [2,3], and on developing and testing new algorithms for the reliable detection of the P300 waveform from noisy datasets [4-8]. For a review of P300, an interested can read the [9-10]. Ten years ago, two pioneer studies have been first published presenting a P300 BCI system on disabled subjects. Piccione et al. (2006) [11] design a 2D cursor BCI control system where subjects had to concentrate on four arrows flashing every 2.5 sec in random order occupied the peripheral area of a computer screen. Five disabled and seven able-bodied subjects were participated on this experiment. For controlling this cursor, this four-choice P300 flashing arrow cursor was used. EEG signals were recorded using four EEG sensors and electro-oculogram. Using independent component analysis and neural networks, Piccione et al. [11] demonstrated that P300 can be a valuable control signal for disabled subjects. However, the communication system was too low compared to state of the art systems [5,8]. Sellers and Donchin (2006) [12] designed a four choice BCI experiment with four stimuli (YES, NO, PASS, END) that were presented every 1.4 s in random order, in two different modalities either visual or auditory or in a combined mode. Three subjects suffering with ALS and three able-bodied subjects performed the experiment. EEG recordings from three sensors were classified using a stepwise linear discriminant algorithm (LDA). They demonstrated that communication via a P300 system is possible for subjects suffering from ALS. Additionally, they demonstrated that communication is possible in different modalities like the visual, auditory, and also in a combined auditory-visual mode. However, both the classification accuracy and the communication rate were low compared to the state of the art results. One of possible explanations of low accuracy and communication rate could be the low number of EEG sensors, the long inter-stimulus intervals and the low number of trials. McCane et al., demonstrated a BCI system where both accuracy and communication rate did not differ significantly between ALS users and HVs. Although ERP morphology was similar for the two groups, the target ERPs differed significantly in the location and amplitude of the late positivity (P300), the amplitude of the early negativity (N200), and the latency of the late negativity (LN) [13]. Hoffmann et al.,, demonstrated a six-choice P300 paradigm which was tested in a population of five disabled and four able-bodied subjects. Six different images were flashed in random order with an ISI of 400 ms [7]. They tested how the electrode configuration can influence the accuracy in order to detect the best channel selection. For four out of five disabled subjects and for all the able-bodied subjects both the communication rates and the classification accuracies were higher compared to the aforementioned studies [11,12]. The datasets in Hoffmann et al., study can be freely downloaded from the website of the EPFL BCI group (http://bci.epfl.ch/p300). In the present study, we used the dataset from Hoffmann et al., study to demonstrate an alternative algorithmic approach with main scope to improve the bitrates up to the limits. For that occasion, we adopted a cross-frequency coupling (CFC) estimator namely phase-to-amplitude coupling (PAC) to quantify how the phase of the lower frequency brain rhythms modulates the amplitude of the higher oscillations. The whole approach was followed in a trial basis and within sensors located over parieto-occipital brain areas. PAC proved to be a valuable estimator in many applications like the design of a biomarker: for amnestic mild cognitive impairment subjects during an auditory oddball paradigm [14], for dyslexia [15], for mild traumatic brain injury [16]. The layout of the paper is as follows. In Section 2, we described the subject population, the experiments that were performed, and the methods used for data pre-processing steps of the proposed pipeline and the classification procedure. Results are presented in Section 3. Discussion is devoted in Section 4. 2. Materials and Methods 2.1. Experimental setup Users were facing a laptop screen on which six images were displayed (see Fig. 1). The images showed a television, a telephone, a lamp, a door, a window and a radio. The images were selected according to an application scenario in which users can control electrical appliances via a BCI system. The application scenario served however only as an example and was not pursued in further detail. The images were flashed in random sequences, one image at a time. Each flash of an image lasted for 100 ms and during the following 300 ms none of the images was flashed, i.e. the inter-stimulus-interval was 400 ms. The EEG was recorded at 2048 Hz sampling rate from 32 electrodes placed at the standard positions of the 10-20 international system. A Biosemi Active Two amplifier was used for amplification and analog to digital conversion of the EEG signals. [Figure 1 around here] 2.2. Subjects The proposed methodology was applied to P300 BCI-oriented recordings derived from five disabled and four healthy subjects. The demographics of the four disabled are presented in (Table 1). Disabled subject 5 as excluded from further analysis. Subjects 6-9 were Ph.D. students that were recruited from EPFL BCI groups laboratory (all males, age 30 ±2.3). None of subjects 6-9 had known neurological deficits. For more information regarding the subjects, an interested reader should refer to the original paper [7]. Table 1. Subjects from which data was recorded in the study of the environment control system S1 S2 S3 S4 Diagnosis Cerebral palsy Multiple sclerosis Late-stage amyotrophic lateral sclerosis Traumatic brain and spinal-cord injury, C4 level Age 56 51 47 33 Age at illness onset 0 (perinatal) 37 39 27 sSex M M M F Speech production Mild dysarthria Mild dysarthria Severe dysarthria Mild dysarthria Limb muscle control Weak Weak Very Weak Weak Respiration control Normal Normal Weak Normal Voluntary eye movement Normal Mild nystagmus Normal Normal 2.3. Experimental schedule Each subject completed four recording sessions. The first two sessions were performed on one day and the last two sessions on another day. All subjects were recruited within maximum two weeks between the first and the last session. Each of the sessions consisted of six runs, one run for each of the six images. For further details about the protocol followed on this experiment see the original paper related to this dataset [7]. The following protocol was used in each of the runs. (i) Subjects were asked to count silently how often a prescribed image was flashed (for example: Now please count how often the image with the television is flashed). (ii) The six images were displayed on the screen and a warning tone was issued. (iii) Four seconds after the warning tone, a random sequence of flashes was started and the EEG was recorded. The sequence of flashes was block-randomized, this means that after six flashes each image was flashed once, after twelve flashes each image was flashed twice, etc. The number of blocks was chosen randomly between 20 and 25. On average 22.5 blocks of six flashes were displayed in one run, i.e. one run consisted on average of 22.5 target (P300) trials and 22.5ÃÆ'-5 = 112.5 non-target (non-P300) trials. (iv) In the second, third, and fourth session the target image was inferred from the EEG with a simple classifier. At the end of each run the image inferred by the classification algorithm was flashed five times to give feedback to the user. (v) After each run subjects were asked what their counting result was. This was done in order to monitor performance of the subjects. The duration of one run was approximately one minute and the duration of one session including setup of electrodes and short breaks between runs was approximately 30 min. One session comprised on average 810 trials, and the whole data for one subject consisted on average of 3240 trials. 2.4 Offline Analysis The impact of different single-sensor recordings on classification accuracy was tested in an offline procedure. For each subject four-fold cross-validation was used to estimate average classification accuracy. More specifically, the data from three recording sessions were used to train a classifier and the data from the left-out session was used for validation. This procedure was repeated four times so each session served once for validation. 2.4.1. Preprocessing Before learning a classification function and before validation, several preprocessing operations were applied to the data. The preprocessing operations were applied in the order stated below. Referencing. The average signal from the two mastoid electrodes was used for referencing. Filtering. A third order forward-backward Butterworth bandpass filter was used to filter the data.. The MATLAB function butter was used to compute the filter coefficients and the function filtfilt was used for filtering. The predefined frequencies were : ÃŽÂ ´ {0.5-4 Hz},ÃŽÂ ¸ {4-8 Hz},ÃŽÂ ±1 {8-10 Hz}, ÃŽÂ ±2 {10-13 Hz},ÃŽÂ ²1 {13-20 Hz},ÃŽÂ ²2 {20-30 Hz} and ÃŽÂ ³1 {30 45 Hz}. (iii) Downsampling. The EEG was down-sampled from 2048 Hz to 512 Hz by selecting each 4th sample from the bandpass-filtered data. (iv) Single trial extraction. Single trials of duration 1000 ms were extracted from the data. Single trials started at stimulus onset, i.e. at the beginning of the intensification of an image, and ended 1000 ms after stimulus onset. Due to the ISI of 400 ms, the last 600 ms of each trial were overlapping with the first 600 ms of the following trial. (v) Electrode selection. We applied our analysis to recordings from single-sensor activity and mainly, PZ,OZ,P3,P4,P7 and P8. (vi) Feature vector construction. As appropriate feature for each trial, we used the phase-to-amplitude coupling (PAC) which already has been shown its potentiality in building reliable biomarkers (Dimitriadis et al., 2015,2016). PAC was estimated for each frequency pair (see ii)). The description of PAC is given in the next section. As a complementary feature that can separate the counted stimuli from the non counted stimuli, alpha relative signal powers have been estimated. Alpha power level can give us a valuable and objective criterion when a subject attends or not attends to the stimulus. Our idea is to create an initial binary classifier that will cut-off the attended from the non-attended stimuli for each subject prior entering the main multi-class classifier. CFC metric computation CFC estimates the strength of pairwise interactions and identifies the prominent interacting pair of frequencies, both between and within sensors [17-19]. Among available CFC descriptors, phase-amplitude coupling (PAC), which relies on phase coherence, is the one most commonly encountered in research [20]. The PAC algorithm as adapted to continuous MEG multichannel recordings is described below. ÃŽÂ ¤he within-sensor CFC version is described. Let x(isensor, t), be the EEG activity recorder at the isensor-th site, and t=1, 2,. T the successive time points. Given a frequency-limited signals x(isensor,t) , cross-frequency coupling is estimated by allowing the phase of the lower frequency (LF) oscillations to modulate the amplitude of the higher frequency (HF) oscillations. The complex analytic representations of each signal zLF(t) and zHF(t) are derived via the Hilbert transform (HT[.]). Next, the envelope of the higher-frequency oscillations AHF(t) is bandpass-filtered within the range of LF oscillations and the resulting signal is submitted to an additional Hilbert transform to derive its phase dynamics component à Ã¢â‚¬  '(t) which expresses the modulation of the amplitude of HF-oscillations by the phase of the LF-oscillations. Phase consistency between the two time-series was measured by means of both the original definition [21] and the imaginary portion of PLV, as synchronization indexes to quantify the strength of PAC. The original PLV is defined as follows: and the imaginary part of PLV as follows: The imaginary portion of PLV is considered to be less susceptible to volume conduction effects in assessing CFC interactions. While the imaginary part of PLV is not affected by volume conduction effects, it could be sensitive to changes in the angle between two signals, which not necessarily imply a PLV change. In general, the imaginary portion of PLV is only sensitive to non-zero-phase lags and is thus resistant to instantaneous self-interactions associated with volume conductance [22]. For further details and applications, an interested reader can read our previous work [14,15]. In the present study, as was already mentioned we used 8 frequency bands which means that PAC is estimated for 7*6/2=21 cross-frequency pairs e.g. ÃŽÂ ´Ãƒ Ã¢â‚¬   ÃŽÂ ¸A ,ÃŽÂ ´Ãƒ Ã¢â‚¬   ÃŽÂ ±1Awhere à Ã¢â‚¬   and A denote the phase and amplitude of each frequency band. Figure 2 demonstrates the pre-processing steps of the PAC estimator for a trial of subject 6 at target image 6. [Figure 2 around here] Signal Power We estimated the relative power of each band-pass frequency signal segment with the following equations: The first equation quantifies the signal power (SP) of each frequency as the sum of the filtered signal squared per sample (3) while equation (4) divides the SP by the sum of the SP from all the frequencies which gives the relative signal power (RSP). The whole approach was repeated for every trial, sessions and subject. 2.4.4. Machine learning and classification Training data sets contained 405 target trials and 2025 non-target trials and validation data sets consisted of 135 target and 675 non-target trials (these are average values cf. Section 2.3). Adopting sequential feature selection algorithm, we detected the characteristic cross-frequency pair via PAC value that gives the highest discrimination of each target images compared to the rest based on the training data set. Additionally, we used the same feature extraction algorithm to detect the relative signal power that separate the counted flashing images from the non-counted images. We trained a multi-class SVM classifier based on the selected PAC estimate from specific cross-frequency pairs and then we tested the classifier to the validation data to get the response tailored to each target image [23]. The training test consisted of the first session while the rest three sessions were used for validating the whole analytic scheme. A k-nearest neighbour (k-NN) classifier was applied to differentiate the attended from the non-attended flashing images prior to multi-class SVM classifier. 2.4.5 Performance Evaluation Classification accuracy and ITR were calculated for the offline experiments separately. The method for calculating ITR (in bits per second) was as follows (5): Where N is the number of classes (i.e., 6 in this study), P is the accuracy of target identification, and T (seconds per selection) is the average time for a selection. Results ÃŽÂ ´-ÃŽÂ ¸ Phase-to-Amplitude Coupling as a Valuable Feature for the BCI-P300 System We estimated both PAC and relative signal power (RSP) for the first 32 samples (60 ms) increasing the window up to 500 ms (256 samples) with a step of 12 samples (5 ms) . The sequential feature selection algorithm detected only one PAC feature from the 21 possible cross-frequency pairs as the unique candidate feature to separate the six classes of images-stimuli. ÃŽÂ ´Ãƒ Ã¢â‚¬   ÃŽÂ ¸A was the selected feature for both disabled and able-bodied subjects. The group-averaged classification performance was for each sensor location using the first 100 ms for both able-bodied and disabled subjects. The errors were detected on the trials where the subject missed the flashing image. The classification performance with the use of a kNN-classifier prior to the multi-class SVM was 100 % for every subject and for all the pre-selected sensors namely PZ,OZ,P3,P4,P7,P8 EEG sensors. Figure 3 and Figure 4 illustrates the trial-related (grand-averaged) PAC-connectivity patterns (comodulograms) for subject 6 (able-bodied) and subject 1 (disabled) correspondingly from target and non-target trials for each flashing image. Comodulograms differed by contrasting target vs non-target within each subject and target image but also between the two images. ÃŽÂ ´Ãƒ Ã¢â‚¬   ÃŽÂ ¸A was the unique feature for both disabled and able-bodied subjects that can clearly predict the target image for both groups. [Figures 3 and 4 around here] Attention and Alpha Power Prior to multi-class SVM, we applied a kNN-classifier based on ÃŽÂ ±1 signal power which was selected as the feature that can discriminate counted from non-counted flashing images. The kNN-classifier performed 100 % clear filtration of attended from non-attended trials for each subject and further improved the performance of multi-class SVM to 100 %. We achieved this performance using ÃŽÂ ±1 signal relative power estimated from the first 100 ms for both able-bodied and disabled subjects. The classification performance with the kNN-classifier was 100 % for every subject and for all the pre-selected sensors namely PZ,OZ,P3,P4,P7,P8 EEG sensors. Table 2 summarizes the group-averaged relative signal power (RSP) of ÃŽÂ ±1 frequency band for attended versus non-attended images. Table 2. Group-averaged ÃŽÂ ±1 signal relative power for attended and non-attended images. Attended Non-Attended Able Bodied Disabled Performance Evaluation In the present study, we succeeded bitrates of 10 bits/sec for both disabled and able-bodied subjects correspondingly for all the sensor locations used on the whole analysis. The time for estimation of PAC and testing the trial was 0.00001 sec on a Windows 7 -Intel 7 8-core machine. Discussion A novel approach of how to analyse single-trials in a BCI system was introduced based on the estimation of cross-frequency coupling (CFC) and namely phase-to-amplitude coupling (PAC). PAC was estimated within EEG sensors from single-trials recorded during a visual evoked experimental paradigm. The proposed analytic scheme based on the extraction of unique features from the CFC patterns on a single-trial basis and namely the ÃŽÂ ´Ãƒ Ã¢â‚¬   ÃŽÂ ¸A coupling, as a unique feature for both able-bodied and disabled subjects. Our experimentations showed a high classification rate (99.7%) based on the proposed PAC feature. Additionally, the superiority of our approach compared to alternative popular methodologies like the use of the original recordings was evident from the succeeded bitrates (10 bits/sec) and also of the response time of the classification system (0.00001 sec). Complementary, using a binary classifier trained with ÃŽÂ ±1 relative signal power prior to the multi-cl ass SVM, we differentiated the attended from the non-attended stimuli which further improved the classification performance up to 100% in both groups. Compared to many other P300-based BCI systems designed for disabled users, we succeeded the highest classification accuracy and bitrates higher than the original presented dataset [7]. In previous studies like the one of Sellers and Donchin (2006) [12], the best classification accuracy for the able-bodied and ALS subjects was on average 85% and 72% correspondingly [12]. Hoffmann et al., succeeded absolute classification accuracy for both disabled and able bodied subjects for the first demonstration of the current dataset. However, he used longer time series of over 15-20 secs by concatenating trials in order to train better the classifier. Additionally, he used one classifier per image per each of the twenty block and the final outcome derived as the majority voting of the twenty classifiers. Here, using phase-to-amplitude coupling as the appropriate descriptor of the evoked response in the parietal brain areas and a multi-class SVM classifier, we performed almost absolute accuracy ( 99.97) on a trial basis. Using an additional binary k-NN classifier and ÃŽÂ ±1 relative signal power prior to multi-class SVM, we separated the attended (counted) from the non-attended (not counted) trials leading to zeroing the misclassified trials from the multi-class SVM classifier for every subject. This procedure further improved the classification performance from 99.97 to 100% for each subject. We succeeded bitrates faster (10 bits/sec) than any other BCI system including the fastest spelling system presented recently (5.32 bits/sec ; [24]). In a previous study of Piccione et al. (2006) [11] average bitrates of about 8 bits/min were reported for both disabled and able-bodied subjects. Hoffman et al., 2008 [7] reported average bitrates obtained with electrode configuration (II) (8 electrodes) 12.5 bits/min for the disabled subjects and 10 bits/min for the able-bodied subjects. According to Klimeschs ÃŽÂ ± theory, on the early stages of perception, ÃŽÂ ± directs the information flow towards to neural substrates that represent information relevant for the encoding system (e.g. visual stimulus to visual system, voice/sound to auditory system). The physiological main function of ÃŽÂ ± is linked to inhibition. Klimeschs ÃŽÂ ± theory hypothesizes that ÃŽÂ ± enables to have access to stored information by inhibiting task-irrelevant neuronal substrates and by timing/synchronizing the cortical activity in task-relevant neuronal systems. A lot of research findings showed that both evoked ÃŽÂ ± and phase locking are evidence of a successful encoding of global stimulus features in an early post-stimulus interval of about 0-150à ¢Ã¢â€š ¬Ã¢â‚¬ °ms [25]. Besides the cross low-frequency/high-frequency coupling (e.g.,ÃŽÂ ¸-ÃŽÂ ³; 26,27), there are many evidences [28-31] that CFC exists also between the low-frequency bands (e.g., delta-theta, delta-alpha, and theta-alpha). Lakatos et al. (2005) [29] introduced a hypothesis about the hierarchical organization of EEG oscillations suggesting that the amplitude of the brain oscillations at a characteristic frequency band can be modulated by the oscillatory phase at lower frequency. In particular, they found that ÃŽÂ ´ (1-4 Hz) phase modulates ÃŽÂ ¸ (4-10 Hz) amplitude, and ÃŽÂ ¸ modulates ÃŽÂ ³ (30-50 Hz) amplitude in primary auditory cortex of awake macaque monkeys [29]. This multiplex coupling or nesting of brain rhythms might reflect a general brain organizational principle, as evidence of coupling (mainly ÃŽÂ ¸-ÃŽÂ ³) has also been observed in animals (e.g. rats,cats) and humans [32]. For instance, in auditory cortex, ÃŽÂ ´-band modulates the amplitude of ÃŽÂ ¸-band ICMs, whose phase in turn modulates the amplitude of ÃŽÂ ³-band ICMs [33]. This indirect enhancement effect uses the ongoing activity of local neural activity in the primary auditory cortex. Their hypothesis supports the notion that neural oscillations reflect rhythmic shifting of excitability states of neural substrates between high and low levels. This hypothesis is supported by the fact that oscillations can be predicted by visual input such as the auditory input arrives during a high excitability phase and is amplified. In the present study, we demonstrated that ÃŽÂ ´ (0.5-4 Hz) phase modulates ÃŽÂ ¸ (4-8 Hz) amplitude over visual brain areas due to flashing images, their content and mainly was observed on parietal EEG recording sites. We should also mention that the reason why ÃŽÂ ´Ãƒ Ã¢â‚¬   ÃŽÂ ¸A coupling discriminates the six flashing images can be directly linked to the content of the images. Visual attention samples image stimuli rhythmically demonstrating a peak of phase at 2 Hz [34] while flashing images induced rhythmic fluctuation at higher frequencies (6-10 Hz) [35] here within ÃŽÂ ¸ frequency range [4-8 Hz].Finally, the work of Karakas et al., ([36]) showed that the ERP represents interplay between the oscillations that are mainly in the ÃŽÂ ´ and ÃŽÂ ¸ frequencies and directly linked to P300 [37]. Conclussion In this work, an efficient algorithmic approach was presented to a P300-based BCI system for disabled subjects. We have shown that absolute classification accuracies and the highest reported bitrates can be obtained for severely disabled subjects under the notion of cross-frequency coupling and namely phase-to-amplitude coupling. Specifically, ÃŽÂ ´ (0.5-4 Hz) phase modulates ÃŽÂ ¸ (4-8 Hz) amplitude proved to be the candidate feature from PAC estimates that supported the highest classification accuracy, the fast bitrates and the fast response time of the multi-class system. Due to the use of the P300, only a small amount of training (trials from 1st session as a training set and 100ms per trial) was required to achieve good classification accuracy. Future improvements to the work presented could be the design of useful BCI applications adapted to the needs of disabled users. Also it might be useful to perform exploratory analysis on larger populations and on real-time to further validate the results found in the present work. Acknowledgements SID was supported by MRC grant MR/K004360/1 (Behavioural and Neurophysiological Effects of Schizophrenia Risk Genes: A Multi-locus, Pathway Based Approach) References Farwell LA, Donchin E. Talking off the top of your head: toward a mental prosthesis utilizing event-related brain potentials. Electroencephalogr Clin Neurophysiol 1988;70:510-23. Polikoff J, Bunnell H, Borkowski W. Toward a P300-based computer interface. In: Proceedings of the RESNA95 Annual Conference; 1995. Bayliss JD. Use of the evoked P3 component for control in a virtual apartment. IEEE Trans Neural Syst Rehab Eng 2003;11(2):113-6. Xu N, Gao X, Hong B, Miao X, Gao S, Yang F. BCI competition 2003 Data Set IIb: Enhancing P300 wave detection using ICA-based subspace projections for BCI applications. IEEE Trans B

Issues of social balance and mixed communities

Issues of social balance and mixed communities Interest in social balance and mixed communities has arisen as a response to both increased management issues in social housing and to concepts of the underclass and social exclusion. The identification of significant and persistent inequalities between areas at the ward and neighbourhood level in recent research (e.g. Meen et al., 2005) has triggered a shift in housing strategy and policy. Social balance is now entrenched within English housing and planning policy where it provides a correction to the housing markets natural tendency to segregate (Goodchild and Cole, 2001). Although this state interventionist approach has come under-fire from academics such as Cheshire (2007), who argue that spatial policy cannot correct deep-rooted social and economic forces and that the focus of policy should be to reduce income inequality in society not just treat the consequences of it, social mixing has gained popular support in urban policy. This literature review outlines the mixed community approach to urban gentrification in urban policy by discussing its latest iteration, the MCI. The MCIs place in UK policy discourse is then analysed as a way of exploring its conceptual and theoretical ideologies for area regeneration. Finally, an in depth review of the literature is conducted which reengages with Mixed Communities as an approach to area regeneration Since 2005, the mixed communities approach to gentrification and the renewal of disadvantaged neighbourhoods has become firmly embedded in the UKs housing and planning policy. The approach was first announced in January 2005 in the Mixed Communities Initiative (MCI) which formed part of New Labours five year plan for the delivery of sustainable communities. The MCI has four core components (Lupton et al., 2009); A commitment to the transformation of areas with concentrated poverty, to provide a better housing environment, higher employment, better education, less crime and higher educational achievements. To achieve these through changes in the housing stock and attraction of new populations, whilst improving opportunities for existing populations. Finance development by recognising the value of publicly owned land and other public assets. Integrate government policies to produce a holistic approach which is sustainable through mainstream funding. Initially the MCI was delivered through twelve demonstration projects situated in the most deprived neighbourhoods in the UK. However, more recently the concepts behind the mixed community approach have grown beyond these projects and are now advocated by planning authorities in a diverse range of areas. Consequently, mixed community developments are emerging without demonstration project status and as such mixed communities have become an approach to area regeneration in addition to being a government policy initiative (Silverman et al., 2006). In response to this policy development the purpose of this literature review is two-fold. Firstly, through analysis of the theories of poverty, place and gentrification in policy discourse it is possible to gain an understanding of the rationale behind the mixed communities conception of the causes place poverty. Review Secondly Theories of Poverty and Place in Urban Policy Any form of urban regeneration reflects a specific theoretical understanding of the causes of place poverty. Throughout the 20th Century UK urban policy has undergone a transformation in its understanding of the causes of place poverty and consequently the approach to urban regeneration has altered. A broad distinction can be made in the UKs approaches to regeneration; between early regeneration by the Keynesian welfare state and that advocated by conservative governments. The former looked to correct the crisis of the neighbourhood through neighbourhood improvement. This approach understands the problems of declining areas as a product of the economic structures which cause spatial and social inequality (Katz, 2004). In response they looked to improve living conditions and try to equalise life chances through redistributive social welfare programmes. In contrast to neighbourhood improvement is the neighbourhood transformation approach, a discernibly neoliberal approach advocated by conservative governments. Here the problems of disadvantaged neighbourhoods are understood as the product of market failures rather than underlying economic structures. The creation of mass social housing estates and overly generous benefit regimes are some of the market failures which reportedly trap the disadvantaged in social cultures of dependency (Goetz, 2003). In the neighbourhood improvement approach these areas are seen as a barrier to market forces; occupying inner city areas with good commercial and residential property investment potential. According to Lupton and Fuller (2009:1016) the neighbourhood improvement approach understands the solution to be: not simply the amelioration of conditions in these neighbourhoods for the benefit of their current residents, but the restoration of market functionality through the physical change and transformation of the position of the neighbourhood in the urban hierarchy Perhaps the best example of this is the role of Urban Development Corporations which brought about the transformation of the London Docklands in the 1980s. Their presence instigated a fundamental change in the role of the state in urban development, from a regulator of the market to an agent within the market. The state was now responsible for fostering the economic conditions under which the economic productivity of areas and communities could be improved. In 1997 New Labours urban regeneration policy was hailed as a divorce from this transformational approach and a return to the improvement approach. The government pioneered an array of new, enhanced public services under the National Strategy for Neighbourhood Renewal. Included was the Neighbourhood Renewal Unit and the New Deal for Communities (NDC) which facilitated interaction between local agents on neighbourhood improvement. Whilst this strategy had the appearance of a strong local focus which prioritised residents, other elements of New Labours policies were characteristically neoliberal. As Fuller and Geddes (2008) remark, Labours urban interventions focus on an equality of opportunity agenda which aspires to greater social cohesion and inclusion by devolving responsibility to local citizens. However, by not matching these responsibilities with appropriate state powers within the NRU and NDC there has been little support for local citizens except to merely compensate the indiv iduals and places put at risk by market forces. As such New Labours initiatives have failed to deliver major redistributional interventions which relinquish local state agents from neoliberal targets, cultures and forms of control (Jessop, 1990). Neoliberal theories of poverty and place within the MCI Within this policy discourse the MCI exists as a more characteristically neoliberal initiative. It is clear in its understanding of the problem, concentrated poverty, and the solution, de-concentration through gentrification and neighbourhood transformation. By doing this the MCI subscribes to a policy discourse which understands concentrated poverty as a spatial metaphor (Crump, 2002). This metaphor inherently undermines complex economic, social and political processes and uses the individual failings of the poor within concentrated spaces to justify their dilution or removal. The concentrated poverty thesis originated from the US (e.g. The Hope VI Urban Revitalisation Programme) where it provides legitimacy to policies which alter cities spatial structures through market forces. Such influences have encouraged British policy makers to adopt a more radical approach to urban regeneration and advocate extensive demolition and gentrification to restore functioning housing markets, imposing a neoliberal agenda on struggling housing environments (Imbroscio, 2008). The MCIs focus on market restoration is clearly articulated: the aim is that success measures should be choice. Reputation, choice of staying and that people want to move in its about market choice (Senior CLG official in Lupton et al., 2009:36) The government realises that while public service improvements will help create this market, it is not enough alone physical change is required to enhance peoples attraction to the neighbourhood and its market. The states role is therefore not just to invest directly but improve and diversify the housing stock whilst decreasing public housing ratios with the explicit goal of stimulating market processes. However, a further consequence of this is the re-population of The mixed communities approach requires the state to fund the improvement of services, in many cases to attract better-off residents, and sell or gift land to the private sector. The removal of social housing through its gift to the private sector inherently creates a spatial fix for poverty and incentivises the development of mixed-income housing developments. In such a situation there is potential for the private sector to change social housing in co-ordinance with market dynamics and consequently complex and marginal developments will be neglected (Adair et al., 2003). CONCLUDE and develop a little mention gentrifiction Impact of Mixed Communities As long as 30 years ago, Holcomb and Beauregard (1981) were critical of the way it was assumed that benefits of urban revitalisation through social mixing would trickle down to the poor. Despite the consequential academic debate, which disputed whether gentrification leads to social exclusion, segregation and displacement, it has become increasingly popular in urban policy where it is assumed that its application leads to a more socially mixed, integrated, and sustainable urban environment. The following review will explore the literature which questions whether moving middle-income populations into low-income neighbourhoods or vice versa has a positive impact on residents urban experience. link to mixed communities Schoon (2001) identifies three rationales behind social mixing in policy debates. Firstly, there is an assumption that the middle-class are more likely to attract public resources and as such the lower-income household will fare better in socially mixed communities. Secondly, mixed income developments are in a better position to support a local economy than areas of concentrated poverty. Finally and most controversially, the networks and contacts argument advocated by Putnam (1995) poses that socially mixed neighbourhoods create an environment which improves the bridging and bonding of social capital between social classes. Consequently, lower-income residents have more opportunities to network and break out of poverty than they would in areas of concentrated deprivation. The Social Exclusion Unit (1998:53) expands on this: [socially mixed neighbourhoods] often brings people into contact with those outside their normal circle, broadening horizons and raising expectations, and can link people into informal networks through which work is more easily found. These three arguments are the cornerstone of a global policy discourse which has received very little critique in the UK. One of the reasons for this is the way it is framed. The social mixing agenda which has been prominent in western efforts to decentralise poverty is a discourse which actively avoids the word gentrification. Instead it uses terms like urban revitalisation, urban regeneration, and urban sustainability to redefine itself as a moral discourse which helps the poor (Slater, 2005; 2006). By doing this the discourse deflects from the class restructuring processes which define its implementation. Previous Studies As of yet there is little consensus around the ability of gentrification to achieve the goals asked of it, neither is it clear what type of social mix is most desirable or the outcomes of different mixes (Walks and Maaranen, 2008). For instance, Tunstall and Fenton (2006) who claim to amass the best UK research on social mix conclude that although knowledge gaps exist the founding arguments for mixed communities remains valid. Yet, in contrast, Doherty et al. (2006) undertook quantitative analysis of the UK census and Scottish Longitudinal Study and concluded that there is little evidence to support the mixing of housing tenures in developments with the premise of improving social well-being. Purpose sentence Randolph and Wood (2003) note that much of the research conducted so far has concentrated on social mixing in public housing estates (Atkinson and Kintrea, 2000; Cole and Shayer, 1998) and there has been little exploration of the social mixing occurring in new build developments. Does Gentrification bring about social mixing? Contrary to the assumptions which link gentrification to improved social mixing, most research suggests that gentrification is likely to reduce social mixing at the neighbourhood level. Interviews conducted by Butler (1997), and Butler and Robson (2001; 2003) suggest that local middle-income gentrifiers engaged in little social interaction with lower-income residents. Their research found that gentrifiers generally sought out people with similar cultural and political interests which often lead to little interaction between middle and low-income residents. Accordingly, they found that interaction was greatest in areas where gentrification had homogenised an area and pushed out other groups. In areas where this had not occurred, Butler and Robson (2001) reported that, the difference between tenants resulted in tectonic juxtapositions which polarised social groups rather than integrating them. In their later research, Butler and Robson (2003) not only reinforced their earlier findings but found that children formed a key facilitator in resident integration: there was no evidence that the children played outside these middle class networks, our fieldwork strongly suggests that the middle class preschool clubs were highly exclusionary of non-middle class children (Butler and Robson, 2003:128) Although Butler and Robsons research rightly questions the role of gentrification in a policy discourse which looks to foster a sustainable urban environment it does so primarily through the experiences of the gentrifier. Davidsons (under review) research of new build, middle income development on the River Thames, London engaged with both gentrifier and non-gentrifier to reinforce scepticism over the ability of housing type to influence class relations. Davidson found no evidence to suggest that any of the developments desired outcomes had been achieved through the introduction of a middle class population. Both the temporary nature of new build residents and the spatially segregated nature of the development itself meant the development fostered little integration between low and middle income residents who do not work in the same place, use the same transport or frequent same restaurants or pubs. In a similar study Freeman (2006) researched two black gentrifying neighbourhoods in New York City. Like Davidson, Freeman found that social networks rarely crossed and that gentrifiers and longer term residents generally moved in different spaces. Additionally, Freeman experienced that residents were hesitant to pass comment on social mixing, they rarely expressed their opinions in overly positive or negative tones. In accordance with this literature it seems unrealistic to assume that different social groups will integrate when living together. As some of the authors have highlighted, increased neighbourhood diversity does not correlate with increased social interaction and can in some cases promote social conflict as much as it does social harmony. Mention how its all based on a class representation of society The mixed communities policy agenda has been used to help improve inequality in social housing (estates managed by local authorities, housing associations, and other non-profit housing agencies) and more controversially to regenerate social housing. This concentration on social housing comes out of a Since its conception social housing in the UK has experienced slow residualisation a tendency to house only certain types of household; the poor, unemployed, those in debt, with a history of mental illness and experiencing a relationship breakdown (Cole and Furbey, 1994). For much of social housings history this process has been ignored and consequently has been accompanied by a sorting process forcing the most vulnerable households into the most unattractive housing (Willmott and Murie, 1988). MIXED COMMUNITIES DEFINE EVERYDAY EXPERIENCE what is encapsulated within this? Social interactionà ¢Ã¢â€š ¬Ã‚ ¦ Previous Studies There are three studies which are relevant to this research. They examine the impact of mixed community housing on social interaction: Atkinson and Kintrea (2000) conducted an exploratory study which analysed diaries made by 38 households. The research suggested that patterns of social life vary by tenure and as such little interaction occurred between residents of owner occupied housing and social housing tenants. The neighbourhood was seen as a focus of interaction for social housing residents only. Cole and Shavers (1998b) survey of 52 residents in a new build, mixed-tenure redevelopment in Sheffield again found only weakly developed social networks. Jupps (1999:10-11) analysis of interviews with over 1,000 residents living in ten-mixed-tenure estates in England, concluded that the street is a more significant social unit than the estate. The case studies analysed often had social and private housing located on different streets and consequently there was little mixing reported between the two groups. Jupp reported that fostering social interaction would extremely difficult because of the overwhelming belief between residents: they do not think that they share many common interests with their neighbours. Individually these studies offer little scope, but taken together they provide a consistent view that mixed tenure developments foster little social interaction between residents of different social backgrounds. However, it must be realised that these studies only examine the grass-roots neighbourhood, that is to say that they often ignore the way external perceptions have defining role in the developments success. Atkinson and Kintrea (2000) identify it as a key area for future research when they report that residents welcomed the influx of higher income residents because they improve the reputation and appearance of the area. There is one fundamental understanding that underpins urban policy in the UK; as stated in the foreword of the Urban White Paper: How we live our lives is shaped by where we live our lives

The Computer’s Positive Impact on Education :: Teaching Learning Essays

The Computer’s Positive Impact on Education Once upon a time there was a teacher and a classroom full of bright and ambitious students. One day a bit of brand new technology was introduced into the classroom. This new technological tool was designed to enable teachers to save time and better instruct groups of students. Students would also be able to utilize this new tool for practicing math problems and spelling words. This new tool is also proven to be very easy to use to compose and edit information on it. In spite of all these wonderful qualities this new advanced technology can bring to the classroom, it was approached with much skepticism. In the early 1900’s, people were concerned and worried about the kinds of problems "the chalkboard" would bring to education! A century later, teacher across the country teachers and students are still successfully utilizing chalkboards in the classroom for teaching and learning. This little story is true and significantly compares to computers entering the education turf. I’m going to take this opportunity to expand on the positive contributions compu ters have and will make in the education field. Computers are having a positive affect on education in many ways. Some of the optimism about computers in education is due to the fact that computers offer diverse collections of resources, variations of media type, increased communications, as well as provision of a records management tool for teachers. The diversity of resources teachers and students have access to through the use of computers is phenomenal. Basically, software and the Internet are the methods used to obtain access to overwhelming amounts of data. The information may be in the form of written material, audio material, games, user-interaction, animation and many more. The Teacher Resource Center (TRC) in Indiana maintains an updated website of teacher resources at "www-ed.fnal.gov/programs/ed_mat_trc.html". Software provides age-appropriate instructional design in the math and science disciplines, as well as in language arts and social studies. Many of these are interactive and/or re-create models of items ranging from complex graphs, historical events, to science experiment labs. Reference libraries are also available on software. There are complete electronic encyclopedia software with color graphics and audio. Information can be printed out, which is convenient for students who are conducting research. Another software area relating to the educational field is pre-school software. Pre-schoolers use computers for "coloring/painting", playing memory games and learning basic letters, numbers, shapes etc.

Athleticism Essay -- Sports, Politics

When I think about the black athlete I experience both pride and discomfort. In America where black people are still politically and economically disenfranchised, it appears that athleticism is the realm where black people excel and dominate. The discomfort comes from the observation that ‘domination’ is only viable when the black male body is harnessed in a way that doesn’t challenge white supremacy in other arenas (Collins, 2005). His body is controlled by contracts of powerful owners, regulated by standardized rules and by-laws from sporting associations and placed in physical spaces where his bodily performance is a spectacle for largely white audiences. There is something historic and normal about the sporting performance that has at once, drawn me in and isolated me. I didn’t quite know why. Ben Carrington’s work Race, Sport and Politics helps me to understand that these boundaries and meanings mark and define ‘the black athlete’ a nd that they can be understood as sites of political struggle. From the onset, I was captivated by his careful and through analysis of various social frameworks in order to utilize sports as a lens to understand the â€Å"intra relationship† between racial discourse, the performance of sport, and the politics in making the ‘black athlete’. In this paper I will explore the various concepts and contentions Carrington discovers as they apply to black males while he tries to formulate a framework to understand the complexity of race and sport and the politics created therein. I will focus on the key concepts essential to creating his theoretical framework specifically, ‘the black athlete’, the ‘white colonial frame’, and the ‘sporting black Atlantic’. The black athlete is a political entity and a global s... ...ind of black humanity. This actor performed feats of brute, physical, endurance, and ‘natural’ prowess which would place him in a category of animalistic sub-humanity. The assumed all body and no mind position of many of the African Diaspora. However within the sanctuary of modern sport, these feats became exceptionally superhuman; a show of raw masculinity and rational dexterity. As a political act, Johnson’s defeat of his white component sent ripples thought the world and attacked the foundation on which the very system that subordinated him was built. Using Carrington’s sense of the sporting black Atlantic. We can fully understand the significance and ramification of this feat. We can come to understand the global implications of this win for black people and see Jackson's â€Å"diasporic politicization† and his rise as an â€Å"anti white supremacist figure (p. 18)†.

Animal Rebellion in Animal Farm

Animal Farm by George Orwell is a story about a group of animals that rebel to get their freedom. It is a story about a society with excellent ideas for progress, that starts with good management, but eventually becomes corrupt. It is a devastating satire on the Russian Revolution. The story elements are matched by a simple prose style. This novel is a straightforward piece of story-telling, which makes the theme of the story pretty clear: totalitarianism is not to be trusted and the communist revolution changed virtually nothing. George Orwell used some literary elements such as plot, characterization, irony, and allusion to present and emphasize the theme of the story. First, Orwell used the plot and characters to present the theme of the story. For instance, the pigs and dogs took most of the power for themselves, thinking they were the best administrators of government. This shows that they were giving themselves attributions and were starting to be unequal. Eventually, the power corrupted them and they killed many of their fellow animals to eliminate competition. Also, Orwell used the pigs to represent the leaders of the Russian government during the 1920†³s, such as Lenin and Stalin. This illustrates how the author used characters, in this case the pigs, to describe the way some leaders acted while they were in charge of their government. Overall, by using a suspenseful but explicit plot, and a personification of animals, Orwell made the reader understand the corruption that surrounded the Russian government. In addition, Orwell used the irony and allusion to present the theme of the story. For example, it is ironic how the animals never remembered any of the commandments clearly, and every time Squealer changed them, nobody noticed it, except Benjamin. This shows how much confidence the animals had on their leaders. They believed that after Mr. Jones had left, now they were supposedly â€Å"their own masters†. Also, Orwell used allusion by presenting a rebellion of animals, which made reference to the Russian Revolution of 1917. This shows how the author used animals to indirectly criticize the leaders of the Russian government during the revolution. By making reference to historical events from the past, the author made a link between the past and present actions and how they relate to one another. Therefore, Animal Farm shows how revolutionary ideals of justice, equality and fraternity always shatter in the moment in which they are going to be practiced. Animal Farm concerns one of the central political experiences of our time: revolution. It is a story about a revolution for an ideal, and about how the ideal is increasingly betrayed until it disappears altogether from the new ociety after the revolution. Because of the corruption within the pig leaders, the animals on the farm ended perhaps even worse than when Mr. Jones was in charge. Every time men and women decide to change the system of government they were born under, there has been a revolution. Orwell is trying to get to the point that revolutions are leading to eventual destruction of society. All in all, there is always going to be a social status that will divide men and economic classes from one another.

Marks and Spencer’s accounting choices Essay

Question 1 Exhibits 1 and 2 report the income statements and excerpts from the notes to Marks and Spencer’s financial statement for the fiscal years ending between March 31, 2005 and March 31, 2009. Critically analyze M&S’s accounting choices. What choices may have helped the company to overstate its net profits between 2005 and 2009? * M&S recognize many software development costs as intangible assets. In fact they recognize all costs related to software costs. This includes direct cost of material and services, payroll related costs for employees who are directly associated with the project. This may help M&S overstate its profits because normally only the direct costs associated with the software are recognized as an asset. The payroll costs for employees should not be considered to be an asset but as direct costs and should immediately reduce profits of M&S. Because this isn’t done, profits can be overstated. This is reflected by the large increase in computer software under development which was 5.6 million in 2005/2004 and was 178.8 million in 2009/2008. This is a stunning increase of 3192%. Besides there isn’t any amortization of the computer under software development and is only subjected to impairment. * Another thing which should be considered when reading the report is that there is a large amount of goodwill which may lead to overstatement of assets. In those five years there isn’t any impairment loss recognized or depreciation on that goodwill. Goodwill should be every year be subjected to impairment and it’s unlikely to remain constant over five years. This may lead to overstatement of assets. Warning signs of delayed write-downs on non-current assets can be a declining non-asset turnover or a declining return on assets below weighted average cost of capital. * Another point of discussion about the accounting methods M&S use, is the large depreciation rates they use on fixtures, fittings and equipment which can vary from three years to 25 years depending on the estimates life of the asset. This should be done on basis of useful economic life instead of the estimated life of the asset. This way they can spread the costs over a larger amount of time which overstates profits. * In 2005-2009, every year there are a large amount of additions, other than acquisitions. This is the case with land and buildings, fixtures, fittings & equipment, goodwill, computer software and computer software and development. Our opinion is that this comes from an increase in value of the asset. This is strange because there is an addition in goodwill which suggests that the value increased with no particular acquisition in 2007/2006 and 2008/2007. Also land and buildings and fixtures fittings & equipment increase because of additions while there is economic downturn in 2008/2007 and 2009/2008. * They also requalify their pension liability as equity because they sold it to a joint venture with its pension fund. This liability was then leased back from the joint venture so because they fully control this operational liability, they can qualify this as equity. This seems to be an accounting trick to state liabilities as equity. M&S also receives exceptional pension credit from this transaction in 2009/2008 and 2008/2007. Question 2 Exhibit 3 provides information about the liability that Marks and Spencer reclassified as equity. Do you agree with the decision to reclassify? What will be the effect of this decision on future financial statements? The reclassification of the liability of Marks and Spencer’s as equity seems to be an accounting trick. Marks & Spencer’s group had a liability of 496.9 million to M&S UK pension scheme. Because they did not want that the liability influenced their financial reports in 2007, they sold it to a joint venture of M&S group with M&S UK Pension scheme. The partnership then leased the properties of the partnership to the M&S plc. This reclassifies the liability because of the operational lease as equity while M&S group still has to pay the money to the pension scheme. When the pension fund has not got the money to pay their employees, the group still has to bring up the money. The effect of this decision on future financial statements is that a large amount of liabilities is classified as equity which distorts the equity/liability ratio and is not an actual reflection of the financial health of the organization. The future financial statements will give off a wrong impression of the liabilities owed to the pension scheme.