Differential spatial modulation for high-rate transmission systems

This paper introduces a new differential spatial modulation (DSM) scheme which subsumes both the previously introduced DSM and high-rate spatial modulation (HR-SM) for wireless multiple input multiple output (MIMO) transmission. By combining the codeword design method of the HR-SM scheme with the encoding method of the DSM scheme, we develop a high-rate differential spatial modulation (HR-DSM) scheme equipped with an arbitrary number of transmit antennas that requires channel state information (CSI) neither at the transmitter nor at the receiver. The proposed approach can be applied to any equal energy signal constellations. The bit error rate (BER) performance of the proposed HR-DSM schemes is evaluated by using both theoretical upper bound and computer simulations. It is shown that for the same spectral efficiency and antenna configuration, the proposed HR-DSM outperforms the DSM in terms of bit error rate (BER) performance

Drug use and pattern of injuries sustained by drivers involved in road traffic crashes

Objective: Road traffic crashes are one of the global public health concerns and remain at high priority in many countries. Driving under the influence of drugs increases the risk of crashes through altering the driver's mental state and reactions. This study was conducted to determine the relationship between driving pattern and substance abuse among drivers in Kerman, a city in Iran, in order to enable policy makers to make the necessary decisions in planning and executing guidelines. Methods: The population of this descriptive study was drivers involved in road traffic crashes admitted to the emergency department of Shahid Bahonar university hospital in summer 2019. After obtaining demographic information, type of vehicle, type of collision and pattern of serious injury, 222 eligible drivers were tested for tramadol, cannabis, amphetamine, methamphetamine, morphine and methadone using one step urine test strips. Chi-square test, Fisher�s exact test, Whitney-Mann and Kruskal-Wallis tests and one-way Anova test was performed using SPSS version 22. Results: The statistics showed that most drivers were male (90.5), married (63.5), age group (18-30) and had positive urine test (76.6). In addition to uniqueness of dual-drug detection among male drivers (7.7), the most common substances detected were methadone and morphine with 34.7 and 27.5 respectively. The most common injuries were lower limb and hip injuries mostly among motorcyclists. The results indicated that characteristics of being under 30�s, married, school dropout, self-employed and motorcyclist had significant relationship with substance use. Conclusions: Substance use, especially methadone, has undoubtedly a significant role in both road traffic crashes and resulted injuries. The high rate of injuries on drivers influenced by methadone in traffic crashes needs to be screened and prevented. It is recommended to not only authoritatively deal with the excessive supply of methadone in the community but also restricting the driving of people receiving methadone treatment. © 2021 Taylor & Francis Group, LLC

Prevalence and predictors of post-traumatic stress disorder and depression among survivors over 12 years after the Bam earthquake

Purpose: The Bam earthquake was one of Iran�s worst natural disasters. As a reason of limited sample size, prevalence and risk factors of PTSD and depression were still unclear after a huge earthquake in Bam. Patients and Methods: A total of 1500 participants selected from the survivors by multi-stage sampling. Instruments included the demographic questionnaire, the PTSD Checklist-Civilian Version and the Beck Depression Inventory-2. Bivariable and multivariable logistic regressions were used to analyze the data. Results: The prevalence rates of PTSD and depressive symptoms were 38.7 (n = 581) and 40.1 (n=597), respectively. The most commonly occurring symptoms of PTSD were distress at reminders (73.7), fear of recurrence (70.3) and sleep disturbance (68.4). Age (OR=1.5, 95 CI= 1.03, 1.74, P < 0.001) and being injured (OR=1.68, 95% CI= 1.09, 2.61, P=0.02) are positive risk factors of PTSD. The risk factors for depressive symptoms were old age (OR= 1.46, 95% CI= 1.02, 1.64, P < 0.001), female gender (OR=1.42, 95% CI=1.14, 1.77, P=0.002), and death of work colleagues (OR=4.03, 95% CI= 1.54, 6.54, P=0.005). Conclusion: Professional and effective mental health services should design programs in order to aid the psychological wellbeing of the population focusing on older adults, females, those who lost work colleagues, and those who lost their family members. © 2020 Divsalar and Dehesh

A memetic algorithm for the orienteering problem with hotel selection

In this paper, a memetic algorithm is developed to solve the orienteering problem with hotel selection (OPHS). The algorithm consists of two levels: a genetic component mainly focuses on finding a good sequence of intermediate hotels, whereas six local search moves embedded in a variable neighborhood structure deal with the selection and sequencing of vertices between the hotels. A set of 176 new and larger benchmark instances of OPHS are created based on optimal solutions of regular orienteering problems. Our algorithm is applied on these new instances as well as on 224 benchmark instances from the literature. The results are compared with the known optimal solutions and with the only other existing algorithm for this problem. The results clearly show that our memetic algorithm outperforms the existing algorithm in terms of solution quality and computational time. A sensitivity analysis shows the significant impact of the number of possible sequences of hotels on the difficulty of an OPHS instance.publisher: Elsevier articletitle: A memetic algorithm for the orienteering problem with hotel selection journaltitle: European Journal of Operational Research articlelink: http://dx.doi.org/10.1016/j.ejor.2014.01.001 content_type: article copyright: Copyright © 2014 Elsevier B.V. All rights reserved.status: publishe