Joint Spectrum Sensing and Resource Allocation for OFDM-based Transmission with a Cognitive Relay

In this paper, we investigate the joint spectrum sensing and resource allocation problem to maximize throughput capacity of an OFDM-based cognitive radio link with a cognitive relay. By applying a cognitive relay that uses decode and forward (D&F), we achieve more reliable communications, generating less interference (by needing less transmit power) and more diversity gain. In order to account for imperfections in spectrum sensing, the proposed schemes jointly modify energy detector thresholds and allocates transmit powers to all cognitive radio (CR) subcarriers, while simultaneously assigning subcarrier pairs for secondary users (SU) and the cognitive relay. This problem is cast as a constrained optimization problem with constraints on (1) interference introduced by the SU and the cognitive relay to the PUs; (2) miss-detection and false alarm probabilities and (3) subcarrier pairing for transmission on the SU transmitter and the cognitive relay and (4) minimum Quality of Service (QoS) for each CR subcarrier. We propose one optimal and two sub-optimal schemes all of which are compared to other schemes in the literature. Simulation results show that the proposed schemes achieve significantly higher throughput than other schemes in the literature for different relay situations.Comment: EAI Endorsed Transactions on Wireless Spectrum 14(1): e4 Published 13th Apr 201

THE COMPARISON OF SUICIDAL THOUGHTS, DEPRESSION, ANXIETY, AND STRESS AMONG ADOLESCENT SUICIDE ATTEMPTERS ABUSING DRUG AND ADOLESCENTS WITHOUT DRUG ABUSE IN ZABOL, 2016

Addiction and drug abuse are among the issues that have been greatly adverted by the clinical psychologists and psychiatrists. Suicide attempt, like other social phenomena, is not uni-causal; a variety of factors affects this phenomenon. Thus, having an exact awareness of suicide factors and studying the importance of the factors seem necessary. The present research aims at studying suicidal thoughts, depression, anxiety, and stress among adolescent suicide attempters abusing drug and adolescents without any drug abuse in Zabol in 2016. The present study is a comparative descriptive-analytical one. The statistical populations of the present study were all the 18-to-29-year-old suicide attempters, with a record of drug abuse referring to Imam Ali Hospital in Zabol in 2016. The data collection tool was depression questionnaire and Beck's suicidal thoughts questionnaire. T-independent and chi-square tests were used for data analysis applying SPSS version 18. The participants' mean age was 14.12 +/- 4.13 years. The drug abusers' mean score of depression, anxiety, stress, and suicidal thoughts were 10.12 +/- 4.16, 7.26 +/- 4.48, 9.02 +/- 4.15, and 18.42 +/- 6.12 respectively. As for the comparison group they were 4.32 +/- 2.18, 4.36 +/- 4.26, 5.16 +/- 4.46, and 6.32 +/- 4.18 respectively (p=0.001). The findings obtained from the T-test for the independent groups indicate the difference in means between the two groups with respect to the degree of depression (p=0.001) and suicidal thoughts (p=0.002). The findings obtained from the present study indicated that variables such as drug abuse, depression, anxiety, and suicidal thoughts are closely related with suicide attempt. Given the comorbidity of drug dependence and other psychiatric disorders, providing educational interventions, executing preventive social plans, and treating psychological disorders for preventing suicide attempts are of great importance

INVESTIGATING THE MORTALITY CAUSES OF 1-59 MONTHS BABIES OF VILLAGE FROM 2012 TO 2015, ZAHEDAN, IRAN

Since the mortality of 1-59 babies is the most serious challenges facing human society and an important indicator of the health and development of countries, providing solutions to reduce this rate as much as possible is of paramount importance. The main objective of the present study is to examine mortality causes of 1-59 months babies in villages under the protection of Zahedan University of Medical Sciences from 2012 to 2015. The present cross-sectional study was conducted through census. The study included the death of all babies registered in Zahedan villages from 2012 to 2015. Required data was collected using raw information form and Child Health Bureau of the Ministry of Health standard questionnaire; SPSS, version 18, was used to process and analyze collected data. The present study examined the death of an overall number of 1252 Zahedan village babies aged between 1 to 59 months; 752 infants aged less than month and this age group turned out to have highest mortality rate; i.e. 60; the lowest mortality rate, 16.7, happened in the age group of 1 to 4 years. The most common causes of death included perinatal disease (29.8), unintentional injuries (17.5), respiratory system diseases (13.2), infectious and parasitic diseases (6.5), congenital and chromosome diseases (6), and cardiovascular disease (2.5). Since the highest mortality rate, 29.8, is related to perinatal diseases of infants, couples pre-pregnancy care and counselling can play crucial role in decreasing the rate of baby, and specially infants, mortality

Transport Properties in Ferromagnetic Josephson Junction between Triplet Superconductors

Charge and spin Josephson currents in a ballistic superconductor-ferromagnet-superconductor junction with spin-triplet pairing symmetry are studied using the quasiclassical Eilenberger equation. The gap vector of superconductors has an arbitrary relative angle with respect to magnetization of the ferromagnetic layer. We clarify the effects of the thickness of ferromagnetic layer and magnitude of the magnetization on the Josephson charge and spin currents. We find that 0-\pi transition can occur except for the case that the exchange field and d-vector are in nearly perpendicular configuration. We also show how spin current flows due to misorientation between the exchange field and d-vector.Comment: 6 pages, 8 figure