Mental tasks classification such as motor imagery based on EEG signals is a challenging issue in brain-computer interface (BCI) systems. Automatic classifier tuning seems to be an essential component ...in real-time BCI systems which makes the interface more reliable and easy to use and may offer the optimum configuration of classifier. This paper investigates the robustness of Least-Square Support Vector Machine (LS-SVM) to classify multi-class self-paced motor imagery (MI) temporal features while tuning the hyperparameters automatically. MI electroencephalogram (EEG) signals were preprocessed and segmented into non-overlapped distinctive time slots. Five different temporal features were extracted to characterize various properties of three Mis. An extended version of LS-SVM was employed for feature classification while the kernel model parameters were tuned by means of two optimization techniques, Coupled Simulated Annealing (CSA) followed by Simplex. LS-SVM parameters were evaluated and selected through leave-one-out cross validation (LOOCV) cost function. Finally, the proposed method was evaluated and compared to three widely used classifiers. The results indicated the high potential of LS-SVM to classify different Mis by obtaining the average classification accuracy 89.88±8.00 when using Sign Slop Changes (SSC) features. However, this LS-SVM performed slowly due to its additional steps for automatic model parameter tuning. In the comparative study, it was shown that each classifier behaved differently when various features were served; however, KNN outperformed others in both terms of classification accuracy and speed.
Pharmacological experiments were conducted to determine the neuronal mechanisms involved in the suppressive effects of the thyrotropin‐releasing hormone analog TA‐0910 on alcohol intake in ...alcohol‐preferring (P) rats. We previously reported that single intraperitoneal injections of TA‐0910 dose‐dependently reduced alcohol intake in P rats without altering fluid or total calorie intake; however, after several consecutive, once‐daily injections, P rats developed tolerance to the suppressive effects of TA‐0910 on alcohol intake and cross‐tolerance to like effects of the dopamine D
2
agonist bromocriptine, but not to like effects of the serotonin uptake inhibitor fluoxetine. In the present study, rats were injected with vehicle or different doses of the D
2
antagonist
s
(–)‐eticlopride (0.01 to 0.05 mg/kg) or the D
1
antagonist
R
(+)‐SCH23390 (0.1 to 0.5 mg/kg) and 20 min later with TA‐0910 (0.75 mg/kg). Alcohol and water intakes were measured at 2,4,6, and 24 hr, and food was measured every 24 hr. Both
s
(–)‐eticlopride and
R
(+)‐SCH23390 produced modest reductions in alcohol intake alone; however, only
s
(–)‐eticlopride antagonized the suppressive effect of TA‐0910 on alcohol intake. In related experiments, it was confirmed that the dopamine D
3
agonist 7‐hydroxy‐
N,N
‐di‐
n
‐propyl‐2‐aminotetralin reduced alcohol intake in P rats, and it was found that tolerance to this effect did not develop during or after seven consecutive once‐daily injections. Furthermore, this effect of 7‐hydroxy‐
N,N
‐di‐
n
‐propyl‐2‐aminotetralin was not diminished in rats made tolerant to the effect of TA‐0910 on alcohol intake. These data, those of previous studies, and recent preliminary findings support involvement of dopamine D
2
, but not D
1
or D
3
receptors in mediating the suppressive effect of TA‐0910 on alcohol intake of P rats.
CMOS phase shifted transmitters for 4G wireless systems Hamedi-Hagh, S.; Salama, C.A.T.
2004 IEEE 15th International Symposium on Personal, Indoor and Mobile Radio Communications (IEEE Cat. No.04TH8754),
2004, Letnik:
1
Conference Proceeding
A novel phase shifted (PS) wireless transmitter architecture is presented. The PS transmitter employs switching power amplifiers, operates without mixers and provides an intermodulation ...distortion-free output spectrum, making it a suitable choice for mobile communication systems. The RF blocks of the PS transmitter include a local oscillator, phase shifters, switching class F power amplifiers and wideband output combiners. The PS transmitter, implemented in a standard 0.18 /spl mu/m CMOS technology, occupies an area of 5 mm/sup 2/. It operates from a 1 V supply and provides 40 dBc adjacent channel power ratio for output bandwidths up to 50 MHz at 8 GHz. The combined class F PAs in the PS transmitter provide 20 dBm output power with a 38% power added efficiency.
A pipelined A/D converter, suitable for cable modem applications is presented. The A/D converter implemented in a 0.25 /spl mu/m CMOS technology provides a resolution of 10 bits at a sampling rate of ...50 MSample/s while dissipating 65 mW from 2.5 V supply voltage. The DNL and INL are -0.5 LSB and 0.95 LSB respectively and the peak SNDR is 57 dB. The total area of the prototype is 3.2 mm/sup 2/ and the core area of the A/D converter excluding pads is 1.2 mm/sup 2/.
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