Multi-BD Symbiotic Radio-Aided 6G IoT Network: Energy Consumption Optimization with QoS Constraint Approach

The commensal symbiotic radio (CSR) system is proposed as a novel solution for connecting systems through green communication networks. This system enables us to establish secure, ubiquitous, and unlimited connectivity, which is a goal of 6G. The base station uses MIMO antennas to transmit its signal. Passive IoT devices, called symbiotic backscatter devices (SBDs), receive the signal and use it to charge their power supply. When the SBDs have data to transmit, they modulate the information onto the received ambient RF signal and send it to the symbiotic user equipment, which is a typical active device. The main purpose is to enhance energy efficiency in this network by minimizing energy consumption (EC) while ensuring the minimum required throughput for SBDs. To achieve this, we propose a new scheduling scheme called Timing-SR that optimally allocates resources to SBDs. The main optimization problem involves non-convex objective functions and constraints. To solve this, we use mathematical techniques and introduce a new approach called sequential quadratic and conic quadratic representation to relax and discipline the problem, leading to reducing its complexity and convergence time. The simulation results demonstrate that the proposed approach outperforms other outlined schemes in reducing EC

Sum Throughput Maximization in Multi-BD Symbiotic Radio NOMA Network Assisted by Active-STAR-RIS

In this paper, we employ active simultaneously transmitting and reflecting reconfigurable intelligent surface (ASRIS) to aid in establishing and enhancing communication within a commensal symbiotic radio (CSR) network. Unlike traditional RIS, ASRIS not only ensures coverage in an omni directional manner but also amplifies received signals, consequently elevating overall network performance. in the first phase, base station (BS) with active massive MIMO antennas, send ambient signal to SBDs. In the first phase, the BS transmits ambient signals to the symbiotic backscatter devices (SBDs), and after harvesting the energy and modulating their information onto the signal carrier, the SBDs send Backscatter signals back to the BS. In this scheme, we employ the Backscatter Relay system to facilitate the transmission of information from the SBDs to the symbiotic User Equipments (SUEs) with the assistance of the BS. In the second phase, the BS transmits information signals to the SUEs after eliminating interference using the Successive Interference Cancellation (SIC) method. ASRIS is employed to establish communication among SUEs lacking a line of sight (LoS) and to amplify power signals for SUEs with a LoS connection to the BS. It is worth noting that we use NOMA for multiple access in all network. The main goal of this paper is to maximize the sum throughput between all users. To achieve this, we formulate an optimization problem with variables including active beamforming coefficients at the BS and ASRIS, as well as the phase adjustments of ASRIS and scheduling parameters between the first and second phases. To model this optimization problem, we employ three deep reinforcement learning (DRL) methods, namely PPO, TD3, and A3C. Finally, the mentioned methods are simulated and compared with each other.Comment: This article will be submitted to the Transactions journa

Low-PAPR Joint Channel Estimation and Data Detection in ZP-OTFS System

Orthogonal Time Frequency Space (OTFS) systems face significant challenges in channel estimation due to high pilot overhead and peak-to-average power ratio (PAPR). To address these issues, we propose a two-step channel estimation method for Zero-Pad OTFS (ZP-OTFS), a modified OTFS system characterized by multiple zero rows along the delay axis. This method strategically inserts pilot sequences into the zero bins of the ZP-OTFS system, effectively mitigating overhead and PAPR. Comprehensive simulation results validate the effectiveness of our proposed method, demonstrating its superior performance over traditional embedded pilot estimation in high Signal-to-Noise Ratio (SNR) scenarios. Specifically, our method achieves a lower normalized mean square error (NMSE) and better bit error rates (BER) at high SNRs

Investigating the safety atmosphere and its associated factors in a construction firm in 2011

Background and Aims: Safety performance in construction industries is a major concern. Occupational injuries and fatalities in these industries are so frequent indicating high rate of accidents. Improper comprehension and safety culture of workers may lead to unsafe behaviors which ultimately result in accidents. This work was conducted to investigate the safety climate and its associated factors in a construction firm.Materials and Methods: A validated questionnaire was used to determine the safety atmosphere and its relevant factors in two sites of a construction firm. According to MORGAN Table, 347 workers of a construction firm were randomly selected. The relations among safety atmosphere factors, as well as demographic characteristics were determined. Spearman’s rho test was used to analysis the data.Results: A meaningful relationship among the safety atmosphere factors was observed in both building workshops according to the Spearman’s rho test. The results also showed that management commitment factor was most associated with stress factors of production. There were significant relationships between age and some safety atmosphere factors such as safety training, production pressure, encouraging raising safety, and rule breaking (p<0.05). Job category had significant relationships with some factors including productionpressure, encouraging raising safety, and safety committees (p<0.05).Conclusion: Safety atmosphere and its associated factors are effective tools to determine the safety condition in the studied construction firm.Key words: Safety climate, Safety climate factors, Accident, Demographical features

Removal of Congo red dye from aqueous solutions by a low-cost adsorbent: activated carbon prepared from Aloe vera leaves shell

Background: Synthetic dyes have several harmful effects on human health as well as aquatic life. In this study, activated carbon (AV-AC), based on Aloe vera leaf shells, was used as a novel agricultural adsorbent, one that is low-cost and available for the removal of Congo red (CR) as a carcinogenic dye from aqueous solutions. Methods: In the batch system, the influence of different parameters like contact time, pH, adsorbent dosage, and initial CR concentration were examined on the dye removal from liquid medium. The experimental data were fitted by pseudo-first-order and pseudo-second-order kinetics, and also Langmuir and Freundlich isotherms models. Results: The optimum contact time and pH for the uptake of CR were obtained at 20 minutes and acidic pH of 2. The maximum uptake capacity of CR dye by AV-AC was 1850 mg/g. The results showed that the experimental data were well-fitted by the pseudo-second-order kinetic model (R2 > 0.99) and Freundlich isotherm model (R2 > 0.99). Conclusion: According to the results of our study, the AV-AC is a low-cost, non-toxic, and effective adsorbent for the uptake of CR dye from aqueous media. Keywords: Aloe Vera, Congo red, Kinetic, Charcoa

Layer-By-Layer Assembly of Graphene Oxide on Thermosensitive Liposomes for Photo-Chemotherapy

Stimuli responsive polyelectrolyte nanoparticles have been developed for chemo-photothermal destruction of breast cancer cells. This novel system, called layer by layer Lipo-graph (LBL Lipo-graph), is composed of alternate layers of graphene oxide (GO) and graphene oxide conjugated poly (l-lysine) (GO-PLL) deposited on cationic liposomesencapsulating doxorubicin. Various concentrations of GO and GO-PLL were examined and the optimal LBL Lipo-graph was found to have a particle size of 267.9 ± 13 nm, zeta potentialof +43.9 ± 6.9 mV and encapsulation efficiency of 86.4 ± 4.7%. The morphology of LBL Lipo-graph was examined by cryogenic-transmission electron microscopy (Cryo-TEM), atomic force microcopy (AFM) and scanning electron microscopy (SEM). The buildup of LBL Lipo-graph was confirmed via ultraviolet-visible (UV–Vis) spectrophotometry, thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) analysis. Infra-red (IR) response suggests that four layers are sufficient to induce a gel-to-liquid phase transition in response to near infra-red (NIR) laser irradiation. Light-matter interaction of LBL Lipo-graph was studied by calculating the absorption cross section in the frequency domain by utilizing Fourier analysis. Drug release assay indicates that the LBL Lipo-graph releases much faster in an acidic environment than a liposome control. A cytotoxicity assay was conducted to prove the efficacy of LBL Lipo-graph to destroy MD-MB-231 cells in response to NIR laser emission. Also, image stream flow cytometry and two photon microcopy provide supportive data for the potential application of LBL Lipo-graph for photothermal therapy. Study results suggest the novel dual-sensitive nanoparticles allow intracellular doxorubin delivery and respond to either acidic environments or NIR excitation. Statement of Significance Stimuli sensitive hybrid nanoparticles have been synthesized using a layer-by-layer technique and demonstrated for dual chemo-photothermal destruction of breast cancer cells. The hybrid nanoparticles are composed of alternating layers of graphene oxide and graphene oxide conjugated poly-l-lysine coating the surface of a thermosensitive cationic liposome containing doxorubicin as a core. Data suggests that the hybrid nanoparticles may offer many advantages for chemo-photothermal therapy. Advantages include a decrease of the initial burst release which may result in the reduction in systemic toxicity, increase in pH responsivity around the tumor environment and improved NIR light absorption

Sludge quality in wastewater treatment plant in Shokohieh industrial Park of Qom province in Iran

The general attitude of the wastewater treatment process in our country is focus on the effluent quality and unfortunately waste sludge quality is rarely considered. Since multiple natural hazards and routes the contact with sludge requires a comprehensive approach to protect public health and the environment. The aim of this study is an assessment of sludge management and finding out the potential use of sludge for land application. The study was conducted in January to December 2014. samples were gathered in four seasons, winter, spring, summer and autumn from wastewater treatment plant in industrial park of Shokohieh of Qom province according to the instructions in standard method. Sampling was moments and composite. Numbers of Samples were 24 that 2 samples were captured in every month. Samples measured base on standard method for water wastewater examination references and then data was analyzed by SPSS and t-test. The results show that the Physical Parameters qualities and nutrients qualities in sludge are good. The Phosphate quality is not suitable. Based on t-test, the results show that levels of fecal coliform and total coliform in cold and warm seasons are different (

Structures for Kalman-based detection over Rayleigh fading channels

grantor: University of TorontoChannel estimation is an essential part of many adaptive detection techniques proposed for data transmission over fading channels. For the frequency selective Rayleigh fading channel an autoregressive representation is proposed based on the fading model parameters. The parameters of this representation are determined based on the fading channel characteristics, making it possible to employ the Kalman filter as the best estimator for the channel impulse response. For IS-136 formatted data transmission, the Kalman filter is employed with the Viterbi algorithm in a Per-Survivor Processing (PSP) fashion and the overall bit error rate performance is shown to be superior to that of detection techniques using the RLS and LMS estimators. To allow more than one channel estimation per symbol interval, Per-Branch Processing (PBP) method is introduced as a general case of PSP. The Kalman filter can lead to significant improvement in the receiver bit error rate performance. However, a Kalman filter is a complex algorithm and is sensitive to roundoff errors. Different implementation methods are considered for measurement update and time update equations of the Kalman filter. The unit-Lower-triangular-Diagonal Correction (LDC) algorithm is used for the time update equations, and systolic array structures are proposed for its implementation. For the overall implementation of joint data and channel estimation, parallel structures are proposed to perform both the Viterbi algorithm and channel estimation. A new approach is proposed for the implementation of the Kalman filter based on differential channel states. This leads to a robust differential Kalman filtering algorithm that can be simplified further to ease the implementation without any major loss in performance.Ph.D