Interacting scalar tensor cosmology in light of SNeIa, CMB, BAO and OHD observational data sets

During this work, an interacting chameleon like scalar field scenario, by considering SNeIa, CMB, BAO and OHD data sets is investigated. In fact, the investigation is realized by introducing an ansatz for the effective dark energy equation of state, which mimics the behaviour of chameleon like models. Based on this assumption, some cosmological parameters including Hubble, deceleration and coincidence parameters in such mechanism are analysed. It is realized that, to estimate the free parameters of a theoretical model, by regarding the systematic errors it better the whole of the above observational data sets to be considered. In fact, if one considers SNeIa, CMB and BAO but disregards OHD it maybe leads to different results. Also to get a better overlap between the counters with the constraint $\chi _{\rm{m}}^2\leq 1$, the $\chi _{\rm{T}}^2$ function could be re-weighted. The relative probability functions are plotted for marginalized likelihood $\mathcal{L} (\Omega_{\rm{m0}} ,\omega_1, \beta)$ according to two dimensional confidence levels $68.3\%$, $90\%$ and $95.4\%$. Meanwhile, the value of free parameters which maximize the marginalized likelihoods using above confidence levels are obtained. In addition, based on these calculations the minimum value of $\chi^2$ based on free parameters of an ansatz for the effective dark energy equation of state are achieved.Comment: Accepted by the European Physical Journal C. 13 pages, 17 figures and 4 tables

Asymptotics of Transmit Antenna Selection: Impact of Multiple Receive Antennas

Consider a fading Gaussian MIMO channel with $N_\mathrm{t}$ transmit and $N_\mathrm{r}$ receive antennas. The transmitter selects $L_\mathrm{t}$ antennas corresponding to the strongest channels. For this setup, we study the distribution of the input-output mutual information when $N_\mathrm{t}$ grows large. We show that, for any $N_\mathrm{r}$ and $L_\mathrm{t}$, the distribution of the input-output mutual information is accurately approximated by a Gaussian distribution whose mean grows large and whose variance converges to zero. Our analysis depicts that, in the large limit, the gap between the expectation of the mutual information and its corresponding upper bound, derived by applying Jensen's inequality, converges to a constant which only depends on $N_\mathrm{r}$ and $L_\mathrm{t}$. The result extends the scope of channel hardening to the general case of antenna selection with multiple receive and selected transmit antennas. Although the analyses are given for the large-system limit, our numerical investigations indicate the robustness of the approximated distribution even when the number of antennas is not large.Comment: 6 pages, 4 figures, ICC 201

Efficiency Analysis of Drive-train for an Electrified Vehicle

In this PhD thesis, various solutions to improve the energy efficiency in the electrical drive-train of an electrified vehicle such as modifications of the propulsion inverter or control of the electric machine, are proposed and their benefits are quantified from an energy efficiency point of view. The efficiency analysis is based on modeling of a power electronics inverter, an electric machine and a battery in various drive cycles for an electrified vehicle.</br> Several solutions are studied for the propulsion inverter. It is shown that by replacing a Silicon pn freewheeling diode in the propulsion inverter with a Silicon Carbide (SiC) diode, an average of up to 1.5 % improvement in the drive cycle efficiency can be expected. Furthermore, by replacing the Silicon IGBTs in the inverter with SiC MOSFETs, the drive cycle efficiency in NEDC can be increased between 2 to 5 percent.</br> Several solutions to improve the efficiency in a PMSM (Permanent Magnet Synchronous Machine) are investigated. An improved MTPA (Maximum Torque per Ampere) is implemented accounting for the variable nature of the machine parameters due to saturation and temperature. Moreover, the iron losses are accounted for in the derivations of an appropriate maximum torque per ampere angle. It is shown that the low-speed and standstill torque characteristics of a selected PMSM with high current density can be improved by 7 % when using a proposed MTPA algorithm instead of an ordinary MTPA algorithm where the equivalent circuit parameters of the PMSM are updated online outside the optimization algorithm. Furthermore, the efficiency can also be improved up to 5 % at the low-speed and high-torque operating region. However, the overall energy efficiency improvement for a certain drive cycle is not significant and can be up to 0.2 %.</br> Finally a controllable dc-link voltage for the propulsion inverter is investigated in order to quantify the energy efficiency gain for the inverter and the motor. Their drive cycle energy efficiency improvement is up to one percent when using a SiC based inverter and up to 4 percent for an IGBT based inverter

On Robustness of Massive MIMO Systems Against Passive Eavesdropping under Antenna Selection

In massive MIMO wiretap settings, the base station can significantly suppress eavesdroppers by narrow beamforming toward legitimate terminals. Numerical investigations show that by this approach, secrecy is obtained at no significant cost. We call this property of massive MIMO systems `secrecy for free' and show that it not only holds when all the transmit antennas at the base station are employed, but also when only a single antenna is set active. Using linear precoding, the information leakage to the eavesdroppers can be sufficiently diminished, when the total number of available transmit antennas at the base station grows large, even when only a fixed number of them are selected. This result indicates that passive eavesdropping has no significant impact on massive MIMO systems, regardless of the number of active transmit antennas.Comment: 7 pages, 2 figures; To be presented in IEEE Global Communications Conference (Globecom) 2018 in Abu Dhabi, UA

Optimal Number of Transmit Antennas for Secrecy Enhancement in Massive MIMOME Channels

This paper studies the impact of transmit antenna selection on the secrecy performance of massive MIMO wiretap channels. We consider a scenario in which a multi-antenna transmitter selects a subset of transmit antennas with the strongest channel gains. Confidential messages are then transmitted to a multi-antenna legitimate receiver while the channel is being overheard by a multi-antenna eavesdropper. For this setup, we approximate the distribution of the instantaneous secrecy rate in the large-system limit. The approximation enables us to investigate the optimal number of selected antennas which maximizes the asymptotic secrecy throughput of the system. We show that increasing the number of selected antennas enhances the secrecy performance of the system up to some optimal value, and that further growth in the number of selected antennas has a destructive effect. Using the large-system approximation, we obtain the optimal number of selected antennas analytically for various scenarios. Our numerical investigations show an accurate match between simulations and the analytic results even for not so large dimensions.Comment: 6 pages, 4 figures, IEEE GLOBECOM 201

Remote preoperative tonic-clonic seizures do not influence outcome after surgery for temporal lobe epilepsy.

OBJECTIVES: Tonic-clonic seizures are associated with greater chance of seizure relapse after anterior temporal lobectomy. We investigated whether the interval between the last preoperative tonic-clonic seizure and surgery relates to seizure outcome in patients with drug-resistant mesial temporal lobe epilepsy (MTLE). METHODS: In this retrospective study, patients were prospectively registered in a database from 1986 through 2014. Postsurgical outcome was categorized as seizure freedom or relapse. The relationship between surgical outcome and the interval between the last preoperative tonic-clonic seizure and surgery was investigated. RESULTS: One-hundred seventy-one patients were studied. Seventy nine (46.2%) patients experienced tonic-clonic seizures before surgery. Receiver operating characteristic curve of timing of the last preoperative tonic-clonic seizure was a moderate indicator to anticipate surgery failure (area under the curve: 0.657, significance; 0.016). The best cutoff that maximizes sensitivity and specificity was 27months; with a sensitivity of 0.76 and specificity of 0.60. Cox-Mantel analysis confirmed that the chance of becoming free of seizures after surgery in patients with no or remote history of preoperative tonic-clonic seizures was significantly higher compared with patients with a recent history (i.e., in 27months before surgery) (p=0.0001). CONCLUSIONS: The more remote the occurrence of preoperative tonic-clonic seizures, the better the postsurgical seizure outcome, with at least a two year gap being more favorable. A recent history of tonic-clonic seizures in a patient with MTLE may reflect more widespread epileptogenicity extending beyond the borders of mesial temporal structures

Knowledge and perceptions of obesity prevention and reducing sugar-sweetened beverages consumption among high school girl students in Shahrekord

Background and aims: The prevalence of obesity among children and adolescents is increasing worldwide. One of the key lifestyle behaviors that helps prevent obesity and being overweight among children and adolescents is to avoid drinking sugar-sweetened beverages (SSBs) or to take, at most, one serving per day. The present study intended to evaluate knowledge and perceptions of high school girl students in Shahrekord on reducing SSBs consumption based on the health belief model (HBM). Methods: The present descriptive-analytical study, conducted in 2013–2014, randomly recruited 308 female students aged 13–14 years. The data were collected using a researcher-made questionnaire based on HBM and a food frequency questionnaire (FFQ). The validity and reliability of the questionnaire were evaluated using face validity, content validity, and inter-rater reliability. The Chi-square test, Pearson’s correlation, and Spearman’s correlation tests were used in SPSS software to analyze the data. The participants declared their informed consent for participation. Results: The research findings showed that the mean score of students’ knowledge was 36.53 ± 21.87; mean scores of perceived susceptibility and perceived severity were 31.88 ± 15.04, and 34.76 ± 19.82, respectively; perceived benefits of reducing the consumption of SSBs was 43.51 ± 20.18, and perceived barriers was 41.56 ± 15.69. There was a direct significant relationship between knowledge and perceived susceptibility as well as between perceived susceptibility and perceived severity. The students’ intake of SSBs was calculated as 2.95 glasses per day. There was a direct significant relationship between perceived benefits and mother’s job, between perceived barriers and father’s job, and between knowledge and mother’s age. There was an inverse relationship between perceived susceptibility and father’s job. Conclusion: Considering the high intake of SSBs among students, along with their little knowledge and perception about its negative effects, it seems necessary to plan for proper educational and theory-based interventions for adolescents in order to improve their knowledge and develop a positive attitude toward reducing SSBs consumption

National Health Information Network: Lessons Learned From the USA and the UK

National Health Information Network (NHIN) is a network in which all health care organizations, government agencies and other health-related organizations are connected to each other to exchange information about health. Due to the necessity of a framework for NHIN development, in this paper, according to the literature review, a definition for NHIN framework was provided, and then the NHIN related projects were reviewed in the United States of America (USA) and the United Kingdom (UK), NHIN and National Programme for Information Technology in the NHS (NPfIT), respectively. The Review of NHIN framework in the countries studied show some similarities and differences in each dimension that are discussed in this framework. NHIN guiding principles in the NHS NPfIT were not regarded or were considered incomplete, compared to the US. NHIN architecture in the US is decentralized while it is centralized in the UK. Based on the review of NHIN framework, these two countries represent important points that can be used in many other countries. However, it can be said that the development of NHIN does not only mean the implementation of national system or systems, or the binding of local health information systems, but It also needs to build on a framework in which many of the issues related to the formation of NHIN would be considered; including the cooperation between government, private sector and stakeholders with regard to local, national and international needs