Outage performance analysis of non-orthogonal multiple access with time-switching energy harvesting

In recent years, although non-orthogonal multiple access (NOMA) has shown its potentials thanks to its ability to enhance the performance of future wireless communication networks, a number of issues emerge related to the improvement of NOMA systems. In this work, we consider a half-duplex (HD) relaying cooperative NOMA network using decode-and-forward (DF) transmission mode with energy harvesting (Ell) capacity, where we assume the NOMA destination (D) is able to receive two data symbols in two continuous time slots which leads to the higher transmission rate than traditional relaying networks. To analyse EH, we deploy time-switching (TS) architecture to comprehensively study the optimal transmission time and outage performance at D. In particular, we are going to obtain closed-form expressions for outage probability (OP) with optimal TS ratio for both data symbols with both exact and approximate forms. The given simulation results show that the placement of the relay (R) plays an important role in the system performance.Web of Science253918

A High-Throughput Hardware Implementation of NAT Traversal For IPSEC VPN

In this paper, we present a high-throughput FPGA implementation of IPSec core. The core supports both NAT and non-NAT mode and can be used in high speed security gateway devices. Although IPSec ESP is very computing intensive for its cryptography process, our implementation shows that it can achieve high throughput and low lantency. The system is realized on the Zynq XC7Z045 from Xilinx and was verified and tested in practice. Results show that the design can gives a peak throughput of 5.721 Gbps for the IPSec ESP tunnel mode in NAT mode and 7.753 Gbps in non-NAT mode using one single AES encrypt core. We also compare the performance of the core when running in other mode of encryption

Conjugate Gradient Approach for Discrete Time Optimal Control Problems with Model-Reality Differences

In this chapter, an efficient computation approach is proposed for solving a general class of discrete-time optimal control problems. In our approach, a simplified optimal control model, which is adding the adjusted parameters into the model used, is solved iteratively. In this way, the differences between the real plant and the model used are calculated, in turn, to update the optimal solution of the model used. During the computation procedure, the equivalent optimization problem is formulated, where the conjugate gradient algorithm is applied in solving the optimization problem. On this basis, the optimal solution of the modified model-based optimal control problem is obtained repeatedly. Once the convergence is achieved, the iterative solution approximates to the correct optimal solution of the original optimal control problem, in spite of model-reality differences. For illustration, both linear and nonlinear examples are demonstrated to show the performance of the approach proposed. In conclusion, the efficiency of the approach proposed is highly presented

A Comparative Study on Process Potentials for Frictional Stir- and Electric Hot-assisted Incremental Sheet Forming

Abstract Incremental sheet forming (ISF), as an advanced forming technique, has received increasing interest from both academia and industry due to its improved formability, greater process flexibility and reduced energy consumption in its life cycle. However, with the growing application of lightweight alloys with very limited material elongation, conventional ISF inevitably encounters challenges in processing these alloys at room temperature, especially in forming magnesium and titanium alloys. Therefore, heat-assisted ISF techniques have been proposed to further enhance material formability at elevated temperatures. In this work, two heat-assisted ISF approaches, frictional stir- and electric hot- assisted ISF, have been employed to process the hard-to-form materials in terms of the flexibility and local dynamic heating. The temperature evolution and corresponding forming force at different feed rates of these two techniques, is investigated in detail to build up a processing window. In addition, process capabilities are compared by forming different geometrical shapes of magnesium alloy AZ31B of 1.4 mm sheet thickness. The investigation results show the pros and cons of frictional stir- and electric hot- assisted ISF. Frictional stir-assisted ISF is more efficient than electric hot-assisted ISF under current experimental results. However, electric hot-assisted ISF has faster heating rate which makes this technique less dependent on the component geometry

Outage performance analysis and SWIPT optimization in energy-harvesting wireless sensor network deploying NOMA

Thanks to the benefits of non-orthogonal multiple access (NOMA) in wireless communications, we evaluate a wireless sensor network deploying NOMA (WSN-NOMA), where the destination can receive two data symbols in a whole transmission process with two time slots. In this work, two relaying protocols, so-called time-switching-based relaying WSN-NOMA (TSR WSN-NOMA) and power-splitting-based relaying WSN-NOMA (PSR WSN-NOMA) are deployed to study energy-harvesting (EH). Regarding the system performance analysis, we obtain the closed-form expressions for the exact and approximate outage probability (OP) in both protocols, and the delay-limited throughput is also evaluated. We then compare the two protocols theoretically, and two optimization problems are formulated to reduce the impact of OP and optimize the data rate. Our numerical and simulation results are provided to prove the theoretical and analytical analysis. Thanks to these results, a great performance gain can be achieved for both TSR WSN-NOMA and PSR WSN-NOMA if optimal values of TS and PS ratios are found. In addition, the optimized TSR WSN-NOMA outperforms that of PSR WSN-NOMA in terms of OP.Web of Science193art. no. 61

BRB System Out-of-Plane Considerations

This paper describes a simple method for BRB system design considering BRB stability and frame out-ofplane deformation effects. The method seeks to prevent yielding in the BRB system except for in the core within the BRB restrainer/casing, and it uses standard equations with which engineers are familiar. The method discourages brace/gusset plate regions which are too flexible, where instability may occur as a result of axial force, or which are too stiff, where yielding may occur due to out-of-plane frame deformations thereby compromising the performance in later in-plane deformation cycles. The need to explicitly consider column twist restraint in the design procedure is emphasized

SỬ DỤNG AXIT OXALIC LÀM CHẤT CHUẨN ĐỂ XÁC ĐỊNH NHU CẦU OXI HÓA HỌC BẰNG PHƯƠNG PHÁP ĐUN HỒI LƯU KÍN – TRẮC QUANG

Potassium hydrogen phthalate (KHP) is used as a standard to determine the chemical oxygen demand (COD) with the closed reflux-colourimetric method (colourimetric method). Besides KHP, it is possible to utilize oxalic acid for this purpose. After boiling at 150 °C for more than 30 minutes in H2SO4 containing Ag2SO4, K2Cr2O7 reacts completely with H2C2O4 at a molar ratio of 1:3. The experimentally determined chemical oxygen demand of H2C2O4 coincides with its theoretical value at 16.0 mg O2/mole H2C2O4. The average COD values of two river water samples, determined with the colourimetric method by using KHP standard and oxalic acid, are not statistically different. Oxalic acid can be used as a standard to determine COD with the colourimetric method.Kali hydro phthalate (KHP) được dùng làm chất chuẩn để xác định nhu cầu oxi hóa học (COD) bằng phương pháp đun hồi lưu kín – trắc quang (phương pháp trắc quang). Ngoài KHP, có thể sử dụng axit oxalic cho mục đích này. Sau khi đun hơn 30 phút ở 150 °C trong môi trường H2SO4 chứa Ag2SO4, K2Cr2O7 sẽ phản ứng hoàn toàn với H2C2O4 theo tỷ lệ mol 1:3. Nhu cầu oxi hóa học của H2C2O4 đã xác định bằng thực nghiệm hoàn toàn trùng khớp với giá trị nhu cầu oxi lý thuyết của hợp chất này là 16,0 mg O2/mol H2C2O4. Nhu cầu oxi hóa học trung bình của hai mẫu nước sông xác định bằng phương pháp trắc quang với hai đường chuẩn dùng KHP và axit oxalic không khác nhau về mặt thống kê. Như vậy, có thể sử dụng axit oxalic làm chất chuẩn để xác định COD bằng phương pháp đã nêu

Outage and bit error probability analysis in energy harvesting wireless cooperative networks

This study focuses on a wireless powered cooperative communication network (WPCCN), which includes a hybrid access point (HAP), a source and a relay. The considered source and relay are installed without embedded energy supply (EES), thus are dependent on energy harvested from signals from the HAP to power their cooperative information transmission (IT). Taking inspiration from this, the author group investigates into a harvest-then-cooperate (HTC) protocol, whereas the source and the relay first harvest the energy from the AP in a downlink (DL) and then collaboratively work in uplink (UL) for IT of the source. For careful evaluation of the system performance, derivations of the approximate closed-form expression of the outage probability (OP) and an average bit error probability ( ABER) for the HTC protocol over Rayleigh fading channels are done. Lastly, the author group performs Monte-Carlo simulations to reassure the numerical results they obtained.Web of Science255746

State Estimation and Optimal Control of Four-Tank System with Stochastic Approximation Approach

This study aims to optimally control the level of a four-tank system at the steady state in the random disturbance environment using the stochastic approximation (SA) approach. Firstly, the stochastic optimal control problem of an equivalent discrete-time is introduced, where the voltages to the pumps are the control inputs. By minimizing the sum of squared errors, the liquid levels are estimated. Then, first-order necessary conditions are derived by defining the Hamiltonian function. Thus, the optimal voltages are calculated based on the estimated liquid levels to update the gradient of the cost function. Finally, for illustration, parameters in the system are considered and a simulation is conducted. The simulation results show that the state estimation and control law design can perform well, and the liquid levels are addressed along the steady state. In conclusion, the applicability of the SA approach for handling a four-tank system with random disturbances is demonstrated

Evaluation of two high-throughput proteomic technologies for plasma biomarker discovery in immunotherapy-treated melanoma patients

Background: Selective kinase and immune checkpoint inhibitors, and their combinations, have significantly improved the survival of patients with advanced metastatic melanoma. Not all patients will respond to treatment however, and some patients will present with significant toxicities. Hence, the identification of biomarkers is critical for the selection and management of patients receiving treatment. Biomarker discovery often involves proteomic techniques that simultaneously profile multiple proteins but few studies have compared these platforms. Methods: In this study, we used the multiplex bead-based Eve Technologies Discovery assay and the aptamer-based SomaLogic SOMAscan assay to identify circulating proteins predictive of response to immunotherapy in melanoma patients treated with combination immune checkpoint inhibitors. Expression of four plasma proteins were further validated using the bead-based Millipore Milliplex assay. Results: Both the Discovery and the SOMAscan assays detected circulating plasma proteins in immunotherapy-treated melanoma patients. However, these widely used assays showed limited correlation in relative protein quantification, due to differences in specificity and the dynamic range of protein detection. Protein data derived from the Discovery and Milliplex bead-based assays were highly correlated. Conclusions: Our study highlights significant limitations imposed by inconsistent sensitivity and specificity due to differences in the detection antibodies or aptamers of these widespread biomarker discovery approaches. Our findings emphasize the need to improve these technologies for the accurate identification of biomarkers