Physical Adversarial Attacks Against End-to-End Autoencoder Communication Systems

We show that end-to-end learning of communication systems through deep neural network (DNN) autoencoders can be extremely vulnerable to physical adversarial attacks. Specifically, we elaborate how an attacker can craft effective physical black-box adversarial attacks. Due to the openness (broadcast nature) of the wireless channel, an adversary transmitter can increase the block-error-rate of a communication system by orders of magnitude by transmitting a well-designed perturbation signal over the channel. We reveal that the adversarial attacks are more destructive than jamming attacks. We also show that classical coding schemes are more robust than autoencoders against both adversarial and jamming attacks. The codes are available at [1].Comment: to appear at IEEE Communications Letter

Large System Analysis of Power Normalization Techniques in Massive MIMO

Linear precoding has been widely studied in the context of Massive multiple-input-multiple-output (MIMO) together with two common power normalization techniques, namely, matrix normalization (MN) and vector normalization (VN). Despite this, their effect on the performance of Massive MIMO systems has not been thoroughly studied yet. The aim of this paper is to fulfill this gap by using large system analysis. Considering a system model that accounts for channel estimation, pilot contamination, arbitrary pathloss, and per-user channel correlation, we compute tight approximations for the signal-to-interference-plus-noise ratio and the rate of each user equipment in the system while employing maximum ratio transmission (MRT), zero forcing (ZF), and regularized ZF precoding under both MN and VN techniques. Such approximations are used to analytically reveal how the choice of power normalization affects the performance of MRT and ZF under uncorrelated fading channels. It turns out that ZF with VN resembles a sum rate maximizer while it provides a notion of fairness under MN. Numerical results are used to validate the accuracy of the asymptotic analysis and to show that in Massive MIMO, non-coherent interference and noise, rather than pilot contamination, are often the major limiting factors of the considered precoding schemes.Comment: 12 pages, 3 figures, Accepted for publication in the IEEE Transactions on Vehicular Technolog

Biostratigraphy of the Ruteh Formation at Harijan section (Central Alborz) northern Iran using foraminifera and conodont

In order to study the fossil contents of the Ruteh Formation for biostratigraphical purposes, the 200 meters thick section was sampled at Harijan section, Central Alborz. The sequence is mainly made up of limestone and shale's. The lower contact of the formation with Dorud Formation is disconform while the upper contact with under learing Dorud Formation is disconformable with overling Nesen Formation is as well as disconformable. Fifty four species belonging to 27 genera (foraminifera and conodonts) were identified and three biozones were differentiated. These are formation: 1- _Schubertella giraudi_- _Codonofusiella distincta_ Assemblage Zone, 2- _Cribrigenerina sumatruna_- _Langella ocarina_ Assemblage Zone, 3- _Sweetognathus whitei_ Biozone. Based on, these an age of Yackhtaschian - Murghabian is quoted to the formation

Effectiveness of Self-Help Mindfulness on Depression, Anxiety and Stress

Introduction: Growing evidence shows that mindfulness based on self-help interventions have advantages for physical and psychological health in different populations. The mindfulness based emotional balance is a new program and efficacy of which has not been investigated in self-help format.  Methods: This study was a randomized control trial (RCT) with wait-list control. After screening and applying inclusion and exclusion criteria eighty students of Kermanshah University of medical sciences were assigned randomly to the mindfulness-based emotional balance self-help or the wait list control group. Anxiety, depression, stress, and mindfulness were measured prior to the intervention after the intervention, and two-month after end of intervention as follow-up. DASS-21 and MAAS were used.  Results: Significant decrease in anxiety, depression, and stress in addition to a significant increase in mindfulness in the experimental group in the posttest. However, there were no significant changes in any of the aforesaid measures in the wait list control group. The resultant benefits were persistent in the two-month follow-up. Conclusion: Based on the results of this study, this type of treatment can be used as an efficient and cost-effective method to improve psychological problems such as stress, depression and anxiety.  Declaration of Interest: Non

Occupational Burnout and Its Related Factors Among Iranian Nurses: A Cross-Sectional Study in Shahroud, Northeast of Iran

BACKGROUND: Good physical and mental health of employees is one of the major characteristics of a healthy organisation. AIM: Due to the importance of occupational burnout and its potentially negative consequences, the aim of this study was to assess occupational burnout and its related factors among Iranian nurses. METHODS: In this cross-sectional study, 205 nurses who were working in two educational hospitals affiliated with Shahroud University of Medical Sciences were included. Forty-two of the nurses were male, and 163 were female (mean age: 31 years). Maslach Occupational Burnout Inventory, demographic and job characteristics questionnaires were completed for each nurse. Questionnaires were then collected, and data were analysed statistically by SPSS, version 22. RESULTS: In the assessment of occupational burnout, the highest level was observed in emotional exhaustion and then in personal performance. There was a significant difference between the frequency of nurses' emotional exhaustion domain in terms of gender (P < 0.05), so that, women suffered more from emotional exhaustion. There was a significant difference between the frequencies of nurses' performance in terms of marital status (P < 0.05) so that married people had more personal performance disorder. CONCLUSION: The results of this study showed that nurses suffered from low occupational burnout. Female gender, sleeping disorders, awakening at night and employment in stressful wards such as the emergency ward was associated with a higher level of occupational burnout in nurses