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Aims Both obesity and heart failure (HF) are associated with sudden cardiac death. The current study aimed to investigate the effects of overweight and HF on the substrate for ventricular fibrillation (VF), and whether renal denervation (RDN) can protect the heart from sympathetic activation and cardiac remodelling in HF rabbits fed with high-fat diet (HFD). Methods and results Twenty-four rabbits randomized into control group fed with regular diet (Control), HFD, HFD-HF, and HFD-HF-RDN groups. Rapid ventricular pacing of 400 b.p.m. for 4 weeks was applied in HFD-HF and HFD-HF-RDN. Surgical and chemical RDNs were approached through bilateral retroperitoneal flank incisions in HFD-HF-RDN. All rabbits received electrophysiological study and a VF inducibility test. The ventricular myocardium was harvested for trichrome stain. After 3 months, mean body weight was heavier in HFD, compared with control (3.5 ± 0.1 kg vs. 2.6 ± 0.1 kg, P Conclusion Our results suggest that overweight and HF increase sympathetic activity, structural remodelling, and VF inducibility, but RDN prevents them.

BACKGROUND The relationship between gastroesophageal reflux disease (GERD) and atrial fibrillation (AF) has been previously reported. However, the detailed mechanism remains unknown. In this study, we investigated the effects of acid reflux on the intrinsic cardiac autonomic nervous system, atrial/ventricular electrophysiology, and AF inducibility. METHODS Eighteen rabbits were randomized into three groups: acid reflux (group 1, n = 6), control (group 2, n = 6), and acid reflux with periesophageal vagal blockade (group 3, n = 6). Atrial and ventricular effective refractory periods (ERPs) and AF inducibility were checked at baseline and then hourly until 5 hours after the experiment. RESULTS Three hours after the experiment, atrial ERP prolongation was noted in groups 2 and 3 (P

Background Autonomic imbalance with increased sympathetic and decreased parasympathetic activities is observed in patients after myocardial infarction (MI). We aimed to investigate sleep-related changed in autonomic regulation in left coronary artery (LCA) ligation rats. Methods Wireless transmission of polysomnographic recording was performed in sham and LCA ligation male rats during normal daytime sleep with and without atenolol treatment. Spectral analyses of the electroencephalogram (EEG) and electromyogram (EMG) were evaluated to define active waking (AW), quiet and paradoxical sleeps (QS, PS). Cardiac autonomic activities were measured by analyzing the power spectrum of heart rate variability (HRV). EEG, EMG and HRV were recorded over 6h for consecutive 3days in all groups. Results In LCA ligation group, there were higher LF and LF/HF ratio on QS phase, but not AW and PS phases, compared to atenolol treated sham and LCA ligation groups, respectively. The HF component was not significantly changed on all groups in both sleep and awake phases. Sleep interruption was more frequent in LCA ligation rats compared to sham, and it was not found in LCA ligation with atenolol treatment group. Increased AW, PS and decreased QS time were noted in LCA ligation group, compared to sham and it was restored to baseline in LCA ligation with atenolol treatment group. Conclusions Our results demonstrate significant sleep fragmentations with sympathetic hyperactivity during QS stages after MI, and atenolol could restore the autonomic dysfunction and sleep disturbance. The finding explains the cause of sleep-related fetal arrhythmia and sudden cardiac death after MI.

Previous studies that demonstrated the well-known “fourth-grade slump” phenomenon mostly adopted the divergent thinking type of creativity measures. The present study distinguishes between open-versus closed-ended creative potentials and predicts their different developmental trends and different relations to the development of children’s reasoning ability. According to Piaget’s cognitive development theory and the dual-process account of creativity theory, open-ended creativity is hypothesised to mainly rely on intuitive, associative Type 1 processing and could be interrupted by the development of formal operations. Closed-ended creativity, on the other hand, involves both Type 1 and Type 2 analytical, evaluative processing, and could benefit from the development of reasoning abilities. The present empirical examinations—with a longitudinal-sequential design—on the task performances of third, fourth, and fifth graders supported the hypotheses. The open-ended creativity indices (the divergent thinking test) exhibited descending trends across age, while the closed-ended creativity measures (the Chinese Word Associates Test and the insight problem-solving task for children) and reasoning abilities (thematic syllogisms) showed ascending trends. The path analysis results further demonstrated that the development of reasoning ability had a significant impact on closed-ended but not open-ended creative potential. The implications of these results and suggested future investigation issues are discussed.

Recent empirical evidence demonstrated that open-ended creativity (which refers to creativity measures that require various and numerous responses, such as divergent thinking) correlated with alpha brain wave activation, whereas closed-ended creativity (which refers to creativity measures that ask for one final correct answer, such as insight problem solving) was related to larger variability in electroencephalogram (EEG) differences between alpha and beta waves. This study designed two EEG neurofeedback procedures to examine their training effects on open- versus closed-ended creative potentials. In the alpha-enhancement condition, participants were reinforced to elevate only their alpha frequencies by auditory feedback for 10 sessions. In the alpha-transformation condition, enhancement and suppression of the signal tone (and hence, the appearance and disappearance of alpha waves) were both practiced. Pre- and posttest comparisons indicated that, compared to the active contrast condition, the alpha-enhan...

Contemporary understanding of brain functions provides a way to probe into the mystery of creativity. However, the prior evidence regarding the relationship between creativity and brain wave patterns reveals inconsistent conclusions. One possible reason might be that the means of selecting creative individuals in the past has varied in each study. By distinguishing creative potential as open-ended versus closed-ended based on theoretical views, this study examined different brain wave patterns and cortical control abilities in relation to different creative potentials by using electroencephalogram (EEG) biofeedback equipment. The results demonstrated that participants’ performance on the open-ended creative problem was positively related to EEG alpha frequencies, whereas performance on the closed-ended creative problem was related to larger variability in EEG dynamics between alpha and beta waves when performing either open-ended or closed-ended creativity tasks. Further, better control in changing states...

This study uses the sol-gel method to synthesize monodispersed hexagonal and six-point star-like gibbsite nanoplatelets by controlling the pH-value of a reaction solution. This method to synthesize gibbsite nanoplatelets is high-yield and produces homogeneous products that disperse well in aqueous solutions. When the reaction is performed at pH = 2.9, the star-like gibbsite nanoplatelets produced are 950 nm in diameter and less than 90 nm in thickness. When the reaction is performed at pH = 2.2, hexagonal gibbsite nanoplatelets are synthesized. Crystal growth can be adjusted through precise control over the reaction concentrations and pH in order to synthesize products with different physical appearances.

Background Ambient fine particulate matter (PM2.5) exposure is associated with increased cardiovascular and cardiac arrhythmias events, but the detailed mechanism remains unclear. Objective We aimed to investigate the effect of PM2.5 (particulate matter Method Among 6912 patients who had underwent 24-hour Holter ECG recordings between Oct 1st 2015 and Oct 31st 2016, 46 (25 males, 69.3 ± 12.1 years old) were enrolled with confirmation of living in an environment with a reported PM2.5 level and were classified as elevated (Group 1, >36 μg/m3, 50.73 ± 8.50) or low (Group 2, Result The baseline characteristics including the comorbidities and medications were similar between the 2 groups. The Holter ECG parameters were also similar. There were no significant HRV differences between the two groups for the 24-hour interval analysis. However, the LF/HF ratio was significantly higher in Group 1 than Group 2 in the 9 am to 9 pm (p = 0.028), 8 am to 4 pm (p = 0.024), and 4 pm to 12 pm (p = 0.025) periods, respectively, but not for the nocturnal HRV parameters. Conclusion Our study demonstrated that an elevated PM2.5 exposure had a significant association with an increased daytime LF/HF ratio suggesting a diurnal difference in the response to PM2.5 exposure.

Background Ventricular tachycardia (VT) and ventricular premature complexes (VPCs) originating from the right ventricular outflow tract (RVOT) are generally considered as benign arrhythmias, with ECG morphology showing LBBB pattern and inferior axis. Pathogenic mechanisms in the genesis of RVOT VT/VPC remain largely unknown. We aimed to investigate the neural mechanism in RVOT ventricular arrhythmias in canine model. Methods Twelve mongrel dogs (13.7 ± 1.3 kg, 5 male dogs) were studied through midline thoracotomies. High-frequency stimulation (HFS) was applied to the proximal pulmonary artery (PA) to induce RVOT VT/VPC. An EnSite Array and a mapping catheter were used for electroanatomical mapping. The RVOT and PA were surgically excised for immunohistochemistry studies, including tyrosine hydroxylase (TH) stain for sympathetic nerves and choline acetyltransferase (ChAT) stain for parasympathetic nerves. Results In nine (75%) out of twelve dogs, HFS of the proximal PA induced RVOT VT/VPC. The density of TH-positive nerves was significantly higher than that of ChAT-positive nerves (6803 ± 700 vs. 670 ± 252 μm2/mm2, p Conclusions HFS of the proximal PA could induce RVOT VT/VPC. The sympathetic nerves were densely innervated to the origin of RVOT VT/VPC, indicating the critical role of sympathetic hyperactivity in the initiation and perpetuation of RVOT VT/VPC.

A new distributed space-time coding (DSTC) scheme is proposed based on a modified cooperation protocol. Comparing the conventional DSTC, the proposed DSTC scheme adopts fewer relay nodes, which can be a flexible scheme when relay nodes are limited. As also shown in the error performance, the proposed DSTC outperforms the conventional DSTC owning to less noise enhancement. Additionally, the proposed DSTC scheme is more economic than the conventional DSTC in spending resource to synchronize the relay network.

Background Frequent ventricular premature complexes ( VPC s) can lead to the development of dilated cardiomyopathy and sudden cardiac death. Renal artery sympathetic denervation ( RDN ) may protect the heart from remodeling. This study aimed to investigate the effect of frequent VPC s on structural and electrical properties and whether RDN can protect the heart from remodeling. Methods and Results Eighteen rabbits were randomized to control (n=6), VPC (n=6), and VPC ‐ RDN (n=6) groups. Surgical and chemical RDN s were approached through bilateral retroperitoneal flank incisions in the VPC ‐ RDN group. Pacemakers were implanted to the left ventricular apex to produce 50% VPC burden for 5 weeks in the VPC and VPC ‐ RDN groups. In addition, ventricular myocardium was harvested for western blot and trichrome stain. Echocardiographic results showed left ventricular enlargement after 5‐week pacing in the VPC group, but not in the VPC ‐ RDN group, when compared to baseline. In biventricles, ion channel protein expressions of Nav1.5, Cav1.2, Kir2.1, and SERCA 2 were similar among 3 groups. However, the degree of biventricular fibrosis was extensive in the VPC group, compared to the control and VPC ‐ RDN groups. Importantly, ventricular fibrillation inducibility was higher in the VPC group (41%) when comparing to the control (13%; P VPC ‐ RDN groups (13%; P Conclusions Frequent VPC s are associated with the development of cardiac structural remodeling and high ventricular fibrillation inducibility. RDN prevents cardiac remodeling and the occurrence of ventricular arrhythmia through antifibrosis.

Background: Right ventricular outflow tract ventricular tachycardia (VT) and ventricular premature complexes (VPCs) are characterized as benign in entity with ECG morphology showing LBBB pattern and inferior axis. Pathogenic mechanisms in the genesis of RVOT VT/VPC remain largely unknown. We aimed to investigate the neural mechanism in RVOT VT/VPC in canine model. Methods: Twelve mongrel dogs (13.7 ± 1.3 Kg, 5 male dogs) were studied through midline thoracotomies. High-frequency stimulation (HFS) was applied to the proximal pulmonary artery (PA) to induce RVOT VT/VPC. An EnSite Array and a mapping catheter were used for electroanatomical mapping. The RVOT and PA were surgically excised for immunohistochemistry studies, including tyrosine hydroxylase (TH) stain for sympathetic nerves and choline acetyltransferase (ChAT) stain for parasympathetic nerves. Results: In nine (75%) out of twelve dogs, HFS of the proximal PA induced RVOT-VT/VPC. The density of THpositive nerves was significantly higher than that of ChAT-positive nerves (6803 ± 700 vs. 670 ± 252 μm2/mm2, p

A series of fluorene-based polymers with alkylsulfanyl, alkylsulfinyl and alkylsulfonyl substituted thiophene were synthesized by the palladium-catalyzed Suzuki coupling reaction and the structures were confirmed by nuclear magnetic resonance spectroscopy and mass spectrometry. The results of the absorption and emission spectra reveal that the substituents on the thiophene ring strongly affect the planarity of the polymer chains. The interruption of the effective conjugation length through the non-planar conformation results in high photoluminescence quantum yield. Cyclic voltammetry analysis of the polymers was observed that the non-planar polymers increased the band gap and decreased the highest occupied molecular orbital level. Differential scanning calorimetry trace confirmed that the less steric hindrance of substituents on the thiophene ring would increase the intermolecular interaction and the crystallinity of the polymers.

This study examines the relationships between two aspects of “breadth of attention” (orienting sensitivity and effortful control) and two forms of creativity (divergent thinking and insight problem-solving). It suggests that the two forms of creativity relate differently to the two modes of attention. This distinction has not been made in previous studies. Intelligence and other personality traits were also assessed as control variables. Over 300 participants’ responses to the Adult Temperament Questionnaire, the Abbreviated Torrance Test for Adults, insight-problem tasks, the HEXACO Personality Inventory, and Raven's Advanced Progressive Matrices were collected. The results showed that, after the effects of intelligence scores and personality traits were controlled for, individuals’ performance on insight problem-solving was predicted only by orienting sensitivity, while effortful control could only predicted divergent thinking performance. The relationships between attentional traits and creative performances were discussed.

This study examined how working memory plays different roles in open-ended versus closed-ended creative problem-solving processes, as represented by divergent thinking tests and insight problem-solving tasks. With respect to the analysis of different task demands and the framework of dual-process theories, the hypothesis was that the idea generation in a divergent thinking test relies more on associative, effortless system 1 processing, but insight problem solving requires rule-based, resource-limited system 2 processing, in addition to system 1 processing. Since system 1 was suggested to be more active in resource deprivation conditions, Experiment 1 adopted the dual-task paradigm, which increased participants' working memory load. The results showed that divergent thinking performance was enhanced and insight problem-solving performance was hindered. Experiment 2 using the individual differences approach found that individuals' working memory capacity correlated with insight problem solving but not with...

Background Heart failure (HF) causes atrial remodeling and increases the incidence of atrial fibrillation (AF). Renal denervation (RDN) has been shown to decrease the development of AF. This study aimed to identify the effects of RDN on the atrial arrhythmogenic substrates in HF. Methods Rabbits were classified into four groups: control (n=9), RDN (n=10), HF (n=6) and HF-RDN (n=9). Surgical and chemical RDN was approached through bilateral retroperitoneal flank incisions in RDN and HF-RDN. Rapid ventricular pacing of 400bpm for 4weeks was applied in HF and HF-RDN. After 4weeks, the rabbits were sacrificed and atrial myocardium were harvested for Western blot and Trichrome stain. Results The bi-atrial effective refractory period (ERP) of HF was significantly longer compared with that of control and RDN. In right atrium, the ERP of HF was also significantly longer compared with that of HF-RDN, but there was no significant difference in left atrial ERP. In bi-atrium, ion channel protein expressions of CaV1.2, NaV1.5, Kir2.1 SERCA2 and NCX were similar among 4 groups. However, the degree of atrial fibrosis was extensive in bi-atrium of HF, when compared to that of control, RDN and HF-RDN. Conclusion The ERP of HF-RDN is partially shortened by RDN compared with that of HF. There are no differences ionic channel protein expressions in bi-atrium among all groups. The degree of atrial fibrosis is severe in HF, but not in HF-RDN, suggesting that RDN may regulate the atrial arrhythmogenic substrates in HF mostly through reverse structural remodeling.

Background Botulinum toxin ( BTX ), temporarily suppressing cholinergic transmission (AF ) for ≥1 year. We aimed to investigate the mechanism underlying long‐term suppression of AF caused by injecting BTX into major atrial ganglionated plexi (GPs). Methods and Results Bilateral thoracotomies in anesthetized dogs allowed programmed stimulation at 4 pulmonary veins, biatrial appendages, and the superior vena cava to determine the effective refractory period ( ERP ) in the first operation. Group 1 (n=10) received BTX injection into all GP s; group 2 (n=7) received no injection. Groups 1 and 2 received rapid atrial pacing (800 bpm) 6 days a week. Group 3 (n=7) did not undergo thoracotomy or rapid atrial pacing to serve as controls for histological studies. A second operation and the same measurements were made 3 months later. During the first operation in group 1, ERP s of 4 pulmonary veins, but not biatrial appendages or superior vena cava, increased immediately after BTX injection. AF burdens increased significantly from the fifth week after the first operation in group 2 but not in group 1. In the second operation, ERP s remained unchanged compared with ERP s before BTX injection in group 1, whereas ERP s shortened significantly at all sites except the superior vena cava in group 2. There was no difference of autonomic nerve density between group 1 and group 3. The GP choline acetyltransferase (+) and atrial tyrosine hydroxylase (+) nerve densities were higher in group 2 than in group 1 and group 3. Conclusions Temporary suppression of major atrial GPs by BTX prevents autonomic remodeling and provides long‐term suppression of AF , indicating the critical role of GPs in AF progression.

In this letter, the realizable direct-sequence code-division multiple-access (DS-CDMA) system occupying Nyquist bandwidth is developed. Several frequently-adopted spreading codes are examined for realization feasibility in the bandlimited DS-CDMA system. It is shown that Nyquist chip-rate transmission can be practically achieved for the bandlimited DS-CDMA system using frequently-adopted spreading codes at the sacrifice of very little user capacity.

In the present study we examine the ways in which gender and personality traits are related to divergent thinking and insight problem solving. According to the dual-process theory account of creativity, we propose that gender and personality traits might influence the ease and choice of the processing mode and, hence, affect 2 creativity measures in different ways. Over 300 participants’ responses on the Abbreviated Torrance Test for Adults (Chen, 2006), HEXACO Personality Inventory (Ashton & Lee, 2009; Lee & Ashton, 2004), Raven’s Advanced Progressive Matrices (Yu, 1993), and performance while conducting insight-problem tasks, are collected. The results show that Openness was positively correlated with divergent thinking performance, whereas Emotionality was negatively correlated with insight problem-solving performance. Women performed better on divergent thinking tests, whereas men’s capabilities were superior on insight problem tasks. Furthermore, Openness exhibited a mediating effect on the relationships between gender and divergent thinking. The relationships among gender, personality, and creative performance, as well as the implications of these findings on cultural differences and real-field creativity, are discussed.

This paper presents a brushless DC (BLDC) motor drive with direct torque control (DTC).The detailed hardware and software design are analyzed and designed. The performance of the BLDC employing DTC is compared with that of BLDC utilizing PWM current control. A prototype of BLDC motor drive based on the DSP controller with DTC control is implemented and validated by the exhibition of waveforms measurement for currents, torque, flux linkage, and speed. The experimental results not only verify the feasibility of designed system but also demonstrate that BLDC with DTC control has superior characteristics than that with PWM current control.

We examined effects of stress, depression, and their interaction on sympathetic-parasympathetic responses, including percentage heart rate (PHR), percentage skin conductance (PSC), percentage finger temperature (PTEMP), and percentage respiratory rate (PRESPR). Participants were categorized into normal, low-risk, and high-risk depression groups under stress or no-stress by measuring psychophysiological responses. Stress increased PHR and PSC and decreased PTEMP. Depression negatively correlated with PHR and PTEMP. PSC and PTEMP were significantly dependent on and positively correlated with depression. PTEMP was significantly affected by the stress and depression interaction. Stress affects sympathetic, rather than parasympathetic, activity. Depression and the interaction between stress and depression initially associated with the sympathetic division and are then correlated with parasympathetic activity. A sympathetic-parasympathetic hypothesis and its clinical implications are discussed. © 2011 Wiley Periodicals, Inc. J Clin Psychol 67:1–12, 2011.

Previous research has found no consistent relationship between measures of disconfirmatory evidence, alternative hypotheses, and people's success in rule-discovery tasks. The present paper explores falsification's inductive benefit under the “context of discovery” in Wason's 2‐4‐6 task by developing a new type of alternative hypothesis, which we label the “new-perspective hypothesis”. Experiment 1 found that falsification is effective only when a new-perspective hypothesis is generated, rather than a same-perspective hypothesis. The total number of alternative hypotheses was also unrelated to rule-discovery success. Experiment 2 replicated Experiment 1 but included the addition of a different name-content task as well as two levels of task difficulty. The main findings were similar to those for Experiment 1, and the new-perspective hypothesis was observed to be most important for the difficult rule-discovery task. These results help to clarify the important ways new-perspective hypotheses and disconfirmat...

A set of novel multi-polar compounds composed of four fluorene-based derivatives with systematic alteration of the molecular structure was synthesized and their nonlinear optical properties in the femtosecond and nanosecond time domain were examined. Preliminary experimental results show that the two-photon activities of the model compounds are connected to structural parameters, such as the number of peripheral electron-donating groups and/or the size of the π-domain in a dye molecule. It is also found that these model chromophores possess large nonlinear attenuation under the irradiation of laser pulses working at nanosecond regimes, indicating that these compounds may have strong two-photon-assisted excited-state absorption within the studied spectral region. Effective optical-power-limiting behaviors of the dendritic fluorophores were also demonstrated to show that such dye molecules can be potential materials for use as broadband and rapid-responsive optical limiters, especially against laser lights with longer pulses.

A constant-power adaptive transmission technique adopting differentially coherent orthogonally multiplexed orthogonal phase modulation (DOMOPM) signals is studied for flat fading channels. Numerical results show that the constant-power adaptive DOMOPM system significantly outperforms the constant-power adaptive noncoherent frequency shift keying system in average spectral efficiency.

Adaptive transmission technique adopting rectangularly-pulsed orthogonally multiplexed modulation (OMM) signals is studied for the flat Rayleigh fading channel. By choosing spectrally efficient OMM signals in accordance with channel status under an error rate constraint, constant-power adaptive OMM systems are shown to significantly outperform the conventional constant-power adaptive orthogonal frequency division multiplexing systems in average spectral efficiency.

Summary Bandlimited direct-sequence code division multiple access (DS-CDMA) attracts much attention for its compact spectrum and the ability to suppress inter-symbol interference. Among the various bandlimited DS-CDMA systems available, minimum-bandwidth DS-CDMA (MB-DS-CDMA) is the only realizable Nyquist rate transmission system. But, MB-DS-CDMA only applies to certain kinds of spreading codes. Accordingly, this study proposes a modified DS-CDMA structure which extends the application of MB-DS-CDMA to all common spreading codes at the expense of a negligible reduction in the transmission rate. Additionally, the bit error rate of the proposed schemes adopting either single-user or multi-user detection receiver is analyzed and compared with that of the commonly-used raised-cosine-pulsed DS-CDMA over multipath fading channels. The numerical results show that given a sufficiently large number of users, the bit error rate performance of modified MB-DS-CDMA is comparable to that of the raised-cosine-pulsed DS-CDMA scheme; meanwhile, the realizable modified MB-DS-CDMA approaches the ultimate transmission rate.

In this study, two kinds of alkaline solutions, sodium hydroxide (NaOH) and sodium silicate (Na2SiO3), with three dosages of 0.5, 1.0 and 1.5% by weight were used to produce the alkali-activated ground granulated blast furnace slag (GGBFS) paste at three different liquid-solid ratios by weight of 0.45, 0.5 and 0.55. Most engineering properties of the paste were examined at age of 3, 7, 14, 28 and 56 days. Experimental results show that a mixed alkaline solution of sodium hydroxide and sodium silicate is necessary to produce an alkali-activated GGBFS paste with adequate workability and strength. Both the liquid-solid ratio and the amount of the alkaline solution affect the compressive strength in the range of 30.38 to 166.22 MPa at age of 28 days. After curing 28 days, alkali-activated GGBFS paste has the coefficient of thermal conductivity and volumetric heat capacity in range of 0.585-0.791 W/m．K and 1.583-1.8 J/m3．K, respectively, which are lower than/close to those of normal weight concrete and thus can be used as a proper material for heat insulation. The microstructural porosity of alkali-activated GGBFS paste is closely related to its engineering and thermal properties.

A high power factor brush less DC motor (BLDC) is designed and implemented in this paper. In order to increase the power factor of a BLDC drive, an active power factor controller is employed to improve the high input current harmonics created from the power diodes as well as the switching of the inverter. The detailed design of the power factor controller is analyzed and implemented. The BLDC drive is also described as well. The experimental results verify the feasibility of BLDC motor drive with designed APFC controller. In addition, the experimental results of a BLDC drive with and without APFC are compared and demonstrated that the former has the power factor correction capability much better than the latter does.

Research into service robots is popular nowaday. In 2006, the RoboCup@home league was founded as part of the RoboCup competition[1]. In contrast to other robot competitions, the venue is an everyday human environment, where the robot has to perform a set of service tasks. This paper describes the design of our RoboCup@home robot based on the mobile U-Bot platform manufactured by the Taiwanese Industrial Technology Research Institute. Our design provides an integrated mobile service robot platform.

Acquisition is the first step in the signal processing section of a Global Position System (GPS) receiver. It detects the presence of a GPS signal received by antenna and provides estimates of code phase and Doppler frequency to the tracking loops. Three acquisition methods in frequency-domain processing are compared, i.e., namely radix-2, split-radix-2/4 and split-radix 2/8 FFTs. The expectancy of the split-radix algorithm is increasing the acquisition efficiency. It is shown that the split-radix-2/8 FFT can save 25% of data loads and stores compared with split-radix-2/4 FFT. The modified Tone detector is applied to enhance the probability of detection. Finally, the acquisition functions are developed in software architecture running on PC.

Propagation delay introduces unwanted delay phase offsets among carriers using different frequencies and deters differential phase demodulation in the hybrid frequency and differential phase modulation systems. Operating on the preamble sequence with two alternately transmitted pulsed carriers, an estimation approach is proposed in this paper to extract the delay phase offsets among carriers using different frequencies. It is shown that delay phase offsets can be reliably estimated when the preamble sequence is sufficiently long.

A power allocation strategy is proposed for single-antenna overlay cognitive radio networks, in which the secondary user helps transmit the signal of the primary user while concurrently conveying its own signal by means of a superposition coding technique. The study commences by deriving analytical expressions for the bit error rates (BERs) of the primary and secondary users. A power allocation strategy is then proposed for minimizing the total power consumption of the two users while simultaneously satisfying their respective BER constraints. The analytical BER formulas are not convex, and hence the optimization process presents a significant challenge. Accordingly, two more tractable BER approximations for the primary and secondary users are proposed to transfer the non-convex problem into a convex one. The simulation results confirm the effectiveness of the proposed power allocation strategy under various channel environments.