Phase-ambiguity resolution for QPSK modulation systems. Part 2: A method to resolve offset QPSK

Part 2 presents a new method to resolve the phase-ambiguity for Offset QPSK modulation systems. When an Offset Quaternary Phase-Shift-Keyed (OQPSK) communications link is utilized, the phase ambiguity of the reference carrier must be resolved. At the transmitter, two different unique words are separately modulated onto the quadrature carriers. At the receiver, the recovered carrier may have one of four possible phases, 0, 90, 180, or 270 degrees, referenced to the nominally correct phase. The IF portion of the channel may cause a phase-sense reversal, i.e., a reversal in the direction of phase rotation for a specified bit pattern. Hence, eight possible phase relationships (the so-called eight ambiguous phase conditions) between input and output of the demodulator must be resolved. Using the In-phase (I)/Quadrature (Q) channel reversal correcting property of an OQPSK Costas loop with integrated symbol synchronization, four ambiguous phase conditions are eliminated. Thus, only four possible ambiguous phase conditions remain. The errors caused by the remaining ambiguous phase conditions can be corrected by monitoring and detecting the polarity of the two unique words. The correction of the unique word polarities results in the complete phase-ambiguity resolution for the OQPSK system

MOLECULAR UNDERSTANDING OF ZWITTERIONS AND QUANTUM COMPUTING FOR SUSTAINABILITY

The sustainable development of society needs sustainable energy solutions and the mitigation of greenhouse gas emissions. One key subject in this area is the development of safe and efficient ion-based batteries. Moreover, CO2 capture is a crucial pathway in mitigating emissions from the combustion of fossil fuels. Ongoing efforts are to improve both technologies\u27 safety and efficiency. This thesis presents our efforts to conduct computational research on understanding advanced zwitterionic electrolytes and CO2 capture. Chapters 2-4 illustrate the computational research to understand ionic solvation in zwitterionic electrolytes. Solid-state electrolytes are essential for safer batteries. While solid polymer electrolytes have advantages such as high safety standards, flexibility, and ease of processing, they suffer from low ionic conductivity. Zwitterionic (ZW) materials have potential due to their unique structures and properties, offering high ionic conductivity and mechanical strength. However, the understanding of their underlying mechanisms and design principles is limited. Our study investigated the effect of ZW molecules in lithium salts and poly(ethylene oxide)-based (PEO) electrolytes through molecular dynamics simulations. We found that ZW molecules can make small Li+ and large anions diffuse at the same level under an electric field and have two distinct effects on Li+ transport and solvation in PEO electrolytes. ZW molecules can release Li+ from the trapping effect of EO chains, enhancing Li+ transport and slowing down Li+ transport by strong Li+-ZW associations. The accelerating effect becomes stronger as the EO chain length increases. We also studied how the chemical structure of ZW molecules affects their ionic disassociation effect and found that MPC, SB, and CB reduce Li+–EO association in the order of MPC \u3e CB \u3e SB (MPC: 2-methacryloyloxyethyl phosphorylcholine, SB: sulfobetaine ethylimidazole, CB: carboxybetaine ethylimidazole). Our simulations suggest that ZW molecule additives may be beneficial in high Li+ concentration environments. At a low Li+ concentration, all three molecules decrease Li+ diffusion, but at a high Li+ concentration, only SB has this effect. Chapter 5 illustrates our effort to develop quantum computing on CO2 capture. Quantum computing has the potential to enhance the efficiency, accuracy, and capabilities of simulating CO2 capture reactions through increased computational power, precision, and resources. In addition to molecular electronic energies, vibrational properties are crucial for understanding reaction kinetics. However, the anharmonicity effect correlates with the molecule size and plays a substantial role in molecular vibrational properties, which can be challenging to address using classical computing. By employing a variational quantum eigensolver algorithm, this work calculates both the molecular electronic and vibrational energies for the reaction pathways between CO2 and NH3. The study showcased the potential of quantum computing for calculating the vibrational energies of large molecules, thus demonstrating its applications in the study of CO2 capture reactions. In summary, this work illustrates the fundamental relationship between the chemical structures of ZW molecules and their ability to alter the ionic solvation and transport in electrolytes. This relationship can be used to rationalize the design of advanced electrolytes with high ionic conductivity. This work also illustrates the potential of quantum computing in enabling the computation of molecular properties critical for CO2 capture and conversion

Quantifying the Inclusivity Quotient: An Examination of Perspectives in Social Journalism

This observe investigates the inclusivity quotient within social journalism, using a quantitative research design to investigate the presence and prominence of uncommon views in digital media content material. Utilizing a purposive sampling approach, three numerous social journalism outlets have been examined over a selected time frame. Descriptive facts revealed a steady 25% illustration of rare perspectives across outlets, with a nuanced analysis of the prominence of those perspectives via overall mentions and average mentions in line with article. Correlation analyses verified superb relationships among the quantity of articles and the visibility of views, emphasizing the interconnected nature of inclusivity variables. The findings spotlight the want for transparent editorial choices to ensure diverse voices aren't best gift but additionally prominent in the virtual narrative. The look at contributes to media diversity discourse with the aid of quantifying inclusivity and providing insights for both practitioners and students

Weighted monotonicity theorems and applications to minimal surfaces in hyperbolic space

We show that there is a weighted version of monotonicity theorem corresponding to each function on a Riemannian manifold whose Hessian is a multiple of the metric tensor. Such function appears in the Euclidean space, the hyperbolic space $\mathbb{H}^n$ and the round sphere $\mathbb{S}^n$ as the distance function, the Minkowskian coordinates of $\mathbb{R}^{n,1}$ and the Euclidean coordinates of $\mathbb{R}^{n+1}$. In $\mathbb{H}^n$, we show that the time-weighted monotonicity theorem implies the unweighted version in \cite{Anderson82}. Applications include upper bounds for Graham--Witten renormalised area of minimal surfaces in term of the length of boundary curve and a complete computation of Alexakis--Mazzeo degrees defined in \cite{Alexakis.Mazzeo10}. An argument on area-minimising cones suggests the existence of a minimal surface in $\mathbb{H}^4$ bounded by the Hopf link $\{zw=\epsilon > 0, |z|^2 +|w|^2 = 1\}$ other than the pair of disks. We give an explicit construction of a minimal annulus in $\mathbb{H}^4$ with this property and obtain by the same method its sister in $\mathbb{S}^4$. A weighted monotonicity theorem is also proved in Riemannian manifolds whose sectional curvature is bounded from above.Comment: 22 pages. Cor 30, Rem 32, Prop 46 added. Overlap with Choe--Gulliver acknowledged. Minor upgrade of Comparison Lemm

MT's algorithm: A new algorithm to search for the optimum set of modulation indices for simultaneous range, command, and telemetry

MT's algorithm was developed as an aid in the design of space telecommunications systems when utilized with simultaneous range/command/telemetry operations. This algorithm provides selection of modulation indices for: (1) suppression of undesired signals to achieve desired link performance margins and/or to allow for a specified performance degradation in the data channel (command/telemetry) due to the presence of undesired signals (interferers); and (2) optimum power division between the carrier, the range, and the data channel. A software program using this algorithm was developed for use with MathCAD software. This software program, called the MT program, provides the computation of optimum modulation indices for all possible cases that are recommended by the Consultative Committee on Space Data System (CCSDS) (with emphasis on the squarewave, NASA/JPL ranging system)

Phase-ambiguity resolution for QPSK modulation systems. Part 1: A review

Part 1 reviews the current phase-ambiguity resolution techniques for QPSK coherent modulation systems. Here, those known and published methods of resolving phase ambiguity for QPSK with and without Forward-Error-Correcting (FEC) are discussed. The necessary background is provided for a complete understanding of the second part where a new technique will be discussed. An appropriate technique to the Consultative Committee for Space Data Systems (CCSDS) is recommended for consideration in future standards on phase-ambiguity resolution for QPSK coherent modulation systems

The Roles of Agricultual Cooperatives in Linking Small Farmers to Set up Large Paddy Fields in Mekong Delta

Agricultural cooperatives play a significant role in linking small farmers to set up large paddy fields in the Mekong Delta. Agricultural cooperatives’ association for establishment of big paddy fields allows firms to purchase secured raw materials in mass quantities, ensuring quality while reducing related costs. Farmers are able to cut down the cost of production, sell products more effectively by gaining economy of scale and have higher position and influence over the businesses. In order to enhance the role of agricultural cooperatives in linking small farmers to establish large paddy fields in the Mekong Delta, it is necessary to synchronously implement the following solutions such as (i) improving mechanisms and policies for agricultural cooperatives to promote their role in farmer linkage to set up large paddy fields; (ii) strengthening the capacity of agricultural cooperatives management staff; iii) strengthening the role of agricultural cooperatives’ representing member farmer households in carrying out the association with firms in setting up big paddy fields. Keywords: Role of agricultural cooperatives, association, large paddy field, Mekong Delta DOI: 10.7176/JESD/10-2-1

Optimization of Superplastic Forming Process of AA7075 Alloy for the Best Wall Thickness Distribution

This work aims to optimize the process parameters for improving the wall thickness distribution of the sheet superplastic forming process of AA7075 alloy. The considered factors include forming pressure p (MPa), deformation temperature T (°C), and forming time t (minutes), while the responses are the thinning degree of the wall thickness ε (%) and the relative height of the product h*. First, a series of experiments are conducted in conjunction with response surface method (RSM) to render the relationship between inputs and outputs. Subsequently, an analysis of variance (ANOVA) is conducted to verify the response significance and parameter effects. Finally, a numerical optimization algorithm is used to determine the best forming conditions. The results indicate that the thinning degree of 13.121% is achieved at the forming pressure of 0.7 MPa, the deformation temperature of 500°C, and the forming time of 31 minutes