Propagation Delay Time Research Articles

Hydrological Drivers of Flooding in Niamey (Niger): The Role of the Sirba River

Abstract In recent decades, floods have become a major global concern. In Niamey (Niger) in West Africa, flooding is primarily caused by the significant increase in surface runoff resulting from heavy rainfall occuring between July and September in the upstream river basins of the three major tributaries of the Middle Niger River (Sirba, Gorouol and Dargol catchments). While the Sirba is empirically considered as the largest driver to flooding in Niamey, its contribution have not been precisely established. This study analyzes the influence of these tributaries on the Niger River discharges at Niamey during the rainy season, with a particular focus on the Sirba River basin. Daily annual maximum discharge (AMAX) data from 1990 to 2022 timeseries are used as inputs to various statistical analyses, including trend analyses, change point detection, concordance analysis and flood dependency assessment. The results reveal a significant change point in 2009 and increasing trends between the Sirba and Niger River stations. The flood propagation time delay varies from 1 to 4 days between the upstream river basins tributaries and Niamey station, with a strong concordance in peak discharges, particularly dominant with the Sirba River. The Dynamic Time Warping (DTW) and the Gumbel copula analyses highlighted the significant control of the Sirba River basin on flooding in Niamey, while also highlighting the important roles played by other tributaries. These findings are crucial for improving flood prevention and further refine urban flood management strategies in Niamey and other cities globally, affected by fluvial floods.

Rectifiable Conductive Thermal Diodes Enabling Thermal Circuits with Selectable Operations for Thermal Logic Applications

AbstractThermal logic paves the way to replace electric logic in scenarios where electronic signals are susceptible to interference or traditional electronics cannot be used, however, is still considered a theoretical and numerical stage. Emerging thermal metalmaterials (TMMs) have the potential to enhance thermal information processes. Compared to TMMs with single‐and‐fixed heat transfer capabilities, rectifiable‐TMMs enable thermal circuits to perform selectable operations, but they are also limited by low operating temperatures and narrow temperature biases. Here, macro‐ and experimental thermal diodes with tree‐like eutectic gallium‐indium/printed polylactic‐acid (EGaIn/PPLA) interface, are demonstrated to be capable of extending asymmetric heat transfer difference to 5.81 times in ambient operation, compared with basic EGaIn/PPLA interface with an input temperature bias of 63.7 °C. Given this, basic thermal gates can be constructed through the incorporation of resistors and a pair of diodes working in the same or opposite directions, with the propagation delay time td within 18 min. Compound logic gates can be cascaded by basic gates in the same way as composed Boolean functions, with td within 4 min. Such thermal circuits prove to perform reliably under dynamic ambient conditions, advancing the engineering of devices designed to manipulate thermal energy and process abundant thermal information.

Timing and scintillation studies of PSR J1439−5501

Context. PSR J1439−5501 is a mildly recycled pulsar in a 2.12-day circular orbit around a heavy white dwarf. A white dwarf cooling model has estimated the companion mass to be between 1 and 1.3 M⊙ and the inclination angle to be greater than 55°. Such high mass and inclination are expected to induce a Shapiro delay, namely, a relativistic time delay in the signal propagation caused by the curved space-time induced by the companion. Until now, however, no Shapiro delay has been measured in this system. Aims. Our aim is to detect the Shapiro delay and, thus, to independently measure the mass and inclination of PSR J1439−5501 by using data from the Parkes and MeerKAT radio telescopes. Methods. The Shapiro delay parameters were measured through pulsar timing, which coherently accounts for every rotation of the pulsar. These measurements were then used to estimate the masses of the component stars and the inclination angle of the binary. A scintillation analysis was additionally performed by investigating the secondary spectra, which are the Fourier-transformed observed scintillation patterns. The obtained secondary spectral variations were analyzed in terms of the orbital motion and annual variation to estimate the ascending nodes, distance, and the location of the screen. Results. We obtained a highly significant measurement of the Shapiro delay, which allows estimates of the pulsar mass (1.57−0.26+0.30 M⊙), the white dwarf (WD) companion mass (1.27−0.12+0.13 M⊙), and inclination angle, (75(1)° or 105(1)°). These estimates assume that the companion mass cannot exceed the Chandrasekhar mass limit (1.48 M⊙), along with a lower limit of 1.17 M⊙ for NS masses. These results are consistent with previous studies, but the precision of the component masses has been improved significantly. The orbital and spin parameters and the large WD mass make this system very similar to that of PSR J2222−0137 and PSR J1528−3146, thereby suggesting a common evolutionary mechanism. The scintillation analysis suggests that the longitude of the ascending node is 16(7)° or −20(6)°, depending on the sense of the inclination angle. The screen distance is 260 ± 100 pc, potentially associated with the edge of the Local Bubble.

Crystallization and microwave dielectric properties of CaO-B2O3-SiO2 glass-ceramic/Al2O3 for LTCC applications

High-frequency electronic devices with low dielectric loss and electronic components with high integration densities require high-performance electronic packaging materials. In this study, materials primarily composed of CaO-B2O3-SiO2 (CBS) with an elevated boron content were fabricated through solid-phase sintering using Al2O3 as the ceramic phase. The phase compositions, densification process, microstructures, thermal conductivity, thermal expansion, and dielectric properties of the LTCC were investigated. Remarkably, the CBS-1 LTCC composite sintered at 850 °C for 4 h, exhibited a dense and nonporous microstructure. It demonstrated exceptional thermoelectric properties, including a thermal shrinkage of 5.61 %, coefficients of thermal expansion of 4.86 ppm/°C, thermal conductivity of 2.36 W/m·K, dielectric constant (εr) of 4.88, and tan δ of 1.05× 10−3 at 15 GHz. These characteristics are conducive to minimizing the signal propagation time delay and filtering noisy signals. Consequently, the CBS-1 LTCC composite emerged as a promising substrate for LTCC applications.

The dynamic analysis of the rumor spreading and behavior diffusion model with higher-order interactions

Rumor spreading occurs not only between two individuals but also among multiple individuals or influenced by groups. However, pairwise interactions in complex networks are insufficient to describe this process. In this study, we propose a rumor spreading model with higher-order interactions, in which the rumor propagation process is represented by simplicial complexes. By selecting the propagation coefficient and time delay as the threshold, the model shows richer dynamic behaviors, such as the bi-stability, discontinuous transition, forward bifurcation, backward bifurcation, Hopf bifurcation, and periodic oscillation. Besides, for exploring the collective behavior induced by rumors, the rumor synchronization model is first established by applying the adaptive feedback mechanism, which erects a theoretical bridge between rumor spreading and behavior diffusion. Moreover, an improved optimal control strategy considering system gains is performed to curb rumor diffusion. Numerical simulations suggest that rumor spreading models with higher-order interactions are more consistent with actual data than network-based ones. Our results may shed some light on comprehending higher-order interactions in rumor spreading and the coupling between rumor and behavior, and provide a promising approach to control rumors and irrational behaviors.

P‐28: High‐speed Oscillator using Polycrystalline InGaO TFTs by Spray Pyrolysis on Polyimide Substrate for Flexible Electronics

We demonstrate high‐performance coplanar thin film transistors (TFTs) on polyimide (PI) substrate, with very thin polycrystalline InGaO (poly‐IGO) thin films deposited by spray‐pyrolysis. The TFTs exhibit saturation mobility (µSAT) of ~39.25 ± 0.73 cm2 V−1 s−1, with excellent uniformity and stable bias stabilities (ΔVTH = +0.3 V for PBTS, ΔVTH = −0.3 V for NBTS). The 7‐stage ring oscillator made of the corresponding TFTs exhibits a very high oscillation frequency of 9.09 MHz at VDD of 15 V with ultra‐low propagation delay time of 7.86 ns/stage.

Time Delay Characterization in Wireless Sensor Networks for Distributed Measurement Applications

This paper investigates the critical aspect of synchronization in wireless sensor networks (WSNs) across diverse industrial applications. The low-cost sensor network topologies are analyzed. The communication delay measurements and quantitative jitter analysis are performed under different conditions, and dependencies of the propagation time delay on the data bitrate and modulation type for different hardware implementations of the WSNs are presented. The time delay distribution influence on the time synchronization error propagation over WSN layers was assessed from the experimental probability density functions. The network synchronization based on the controlled propagation delay jitter approach has been proposed. This research contributes quantitative insights into the complexities of synchronization in WSNs, offering a foundation for optimizing network configurations and parameters to extend the operational life of low-power sensor nodes.

Differential Correction Method of Long-Wave Propagation Time Delay Applied to Complex Long-Distance Path

Differential Correction Method of Long-Wave Propagation Time Delay Applied to Complex Long-Distance Path

Improved post-radiation behavior of FinFET based CMOS with workfunction modulated gate

The total ionizing dose (TID) effect of modulated gate workfunction (MGW) FinFET based CMOS inverter is designed and analyzed. The post radiation analysis of the voltage transfer characteristics, noise margin and propagation delay are demonstrated. The incorporation workfunction modulation engineering enhances the OFF-state performance, and maintains positive threshold voltage for both the pre and post radiation condition. 2-decade improvement is noticed for the both n-FinFET and p-FinFET. In addition, the proposed technique offers minimum propagation delay time and acceptable noise margin range even after 2000 krad of radiation dose. The analysis and comparison of the results is done by the 3-D TCAD simulator.

Map-aiding of the additional secondary factors isosurface by the spline approximation method as a condition of improving the e-Loran observations accuracy

The benefit of the Loran ground-based radio navigation system as an alternative to global navigation satellite systems is argued. The motivation of searching for a duplicate variant is caused by the necessity to ensure the reliability of positioning as a subject of countering spoofing and jamming risks when implementing the concept of cybernetic awareness on water transport. Hypothetically, the possibility of using e-Loran on the Northern Sea Route as a backup navigation system is considered. The experience of operating pilot projects of the enhanced Loran in the issue of the predicted potential of positioning accuracy is analyzed. The optimal method of compensation for the system error of geolocation based on the use of additional secondary factors is investigated. Taking into account the principle of the d-Loran functional, based on comparing the measured values of the radio signal passage delay with published analogues for transmitting clarifications to marine consumers, the necessity of using integrity as a criterion for a confidence assessment of the navigation information processing reliability has been determined. A critical analysis of the attempts effectiveness to use the linear interpolation method to calculate intermediate representative values of the delay in the radio signal transmission in order to simulate the map of additional secondary factors is performed. The hypothesis of the prospects for the isosurface corrections synthesis based on B-spline approximation is put forward. The South Korean experiment of synthesizing a chart of additional secondary factors with measured indicators of the radio signal propagation time delay in nanoseconds from the Pohang transmitting station has been repeated at the correct algorithmic level. In order to demonstrate the practical feasibility of the spline algorithm, a computer visualization of a cartographic fragment of additional secondary factors of Yongil Bay is performed. It is suggested that three-dimensional representation of the additional secondary factor for situational perception by the Officer on watch of map-aided correction as a process in alternative positioning in order to increase the reliability of location control through visual evaluation of proper use of corrections of the e-Loran differential variant. The prospect of using the developed package of applied Pascal-programs with implementations on display-type monitors as intellectual support for decision-making by the navigator in a posteriori assessment of the observation accuracy due to the visual representation of the correction field is noted.

Experimental Study on the Explosion Parameters of n-Decane Aerosol under Saturated Vapor Pressure.

This research aims to conduct a comprehensive investigation and analysis of the effects of particle size and concentration on crucial explosion parameters in n-decane aerosols. Two sets of n-decane aerosols with different concentrations were initially measured, with Sauter mean diameters of 22 and 38 μm, respectively. These measurements served as the foundation for understanding the impact of the particle size on explosion parameters. Subsequently, experiments were performed on n-decane aerosols with various concentrations, utilizing an ignition energy of 40.32 J. The analysis focused on critical explosion parameters including the lower flammability limit, explosion pressure, explosion temperature, and flame propagation delay time. Through thorough examination of the data obtained from these experiments, the research elucidated the relationship between n-decane concentration, particle size, and these explosion parameters.

Design of silicon slab waveguides based all‐optical logic gates

AbstractLogic gates are an indispensable part of digital circuits, and therefore such devices with fast operating speeds and simple designs are vital for all kinds of electronic applications. This paper proposes simple Y‐shaped designs of all‐optical AND, OR, and NOT logic gates in two dimensions that are operational in both TE and TM modes. These gates are designed using silicon slab waveguides, which makes them relatively easy to fabricate. The logic gates are designed, analyzed, and optimized at 1.55 µm using the finite difference time domain method. The truth tables of the proposed all‐optical logic gates are realized for every input case. The propagation delay time is determined to be of the order of femtoseconds (10−15 s), which is very fast compared to the response time of the currently reported all‐optical logic gates (10−9 ‐ 10−12 s).

Localization of a Passive Object in 3-D by Propagation Time Delays to a Rigid Body Receiver of Unknown Location

Localization of a Passive Object in 3-D by Propagation Time Delays to a Rigid Body Receiver of Unknown Location

Intermittent behavior near the boundary of generalized synchronization in unidirectionally coupled time-delayed systems

The aim of the work is an analysis of characteristics of intermittent behavior taking place near the boundary of generalized synchronization in unidirectionally coupled time-delayed generators. The case of interaction of systems characterized by different numbers of positive Lyapunov exponents is considered. To determine the lengths of characteristic phases of the system behavior the auxiliary system method has been used. The result of the work is the determination of the type of intermittency taking place near the boundary of generalized synchronization. In this case by calculation the statistical characteristics of the laminar phase lengths (distributions of the laminar phase lengths and the dependencies of the mean lengths of the laminar phases on the criticality parameters) it has been found that near the boundary of the synchronous regime the on-off intermittency is observed. It has been shown that the intermittent generalized synchronization in time-delayed systems is characterized by multistability. For these purposes a time-averaged measure of multistability depending on the value of the coupling parameter between systems has been calculated and compared with the behavior of the spectrum of Lyapunov exponents. It has been found that the multistability measure can be used to detect the generalized synchronization in time-delayed systems.

Study on the regional ASF prediction method based on the ordinary kriging interpolation

The eLoran system functions as a robust backup to the Global Navigation Satellite System (GNSS), providing substantial signal power, robust anti-jamming capabilities, and an easily maintainable ground system. Nonetheless, the propagation time delay of the system, primarily driven by the Additional Secondary Phase Factor (ASF), significantly influences the positioning accuracy. Compensating for ASF can effectively enhance the positioning performance. Traditional propagation delay theories frequently yield substantial discrepancies between the predicted and measured values in regions characterized by extended propagation distances and varying topographic features. To address this issue, we conducted ASF measurements within a selected test area using a limited number of measurement points. We employed the ordinary Kriging interpolation method to predict ASF values across the entire test area, and used cross-validation to validate our predictions. The results confirmed the accuracy and effectiveness of the Kriging interpolation algorithm in predicting ASF values within specific regions. The cross-validation demonstrated that the errors remained within acceptable ranges. Furthermore, we applied Ordinary Kriging, Inverse Distance Weighting, and Radial Basis Function Interpolation methods to evaluate the positioning accuracy of the test area before and after ASF correction. Compared to other methods, using the Ordinary Kriging interpolation algorithm for predicting ASF values resulted in a corrected positioning accuracy of up to 68.8 m at various test locations. This approach effectively resolves the challenge of low accuracy in theoretical calculations in complex environments. By utilizing ordinary Kriging interpolation, we required measurements of only a few ASF values within a specific region to create an ASF correction map, addressing the challenges related to inaccurate theoretical calculations in complex pathways and avoiding time-consuming and labor-intensive large-scale measurements. The results of this study offer valuable theoretical support for improving the accuracy of land-based navigation systems.

Time-delayed generalized BSDEs

We prove the existence and uniqueness of the solution of a BSDE with time-delayed generators in the small delay setting (or equivalently small Lipschitz constant), which employs the Stieltjes integral with respect to an increasing continuous stochastic process. Moreover, we obtain a result of continuity of the solution with regard to the increasing process, assuming only uniform convergence, but not in variation. We also prove the existence in the case of arbitrary delay by imposing monotonicity and linearity on generators. Lastly, we provide an application of the theoretical framework within an insurance based example.

Quantum enhancement of qutrit dynamics of a three-level giant atom coupling to a one-dimensional waveguide

Dynamics of quantum coherence and non-Markovianity of a three-level giant atom coupling to a one-dimensional waveguide and a classical field are investigated theoretically. The time delay of the photo propagation in the waveguide is taken into account and our aim is to access the collective impact of a waveguide and classical control of the system on the time evolution of coherence and non-Markovianity. For a giant atom, we find that the various values of the accumulated phase and time delay does not make much difference for the coherence evolution but there exists non-Markovian behavior for the vast majority of the chosen parameter values. With regard to the initial relative phase, the quantum coherence takes a monotonic behavior for a small atom but decreases with oscillations for a giant atom with majority values of the initial relative phase. Quantum coherence of a small atom decreases monotonically with regardless of the Rabi frequency and the atom’s detuning to a large extent but a large Rabi frequency or a large atom’s detuning will induce non-Markovian behavior for a giant atom. With a comparative analysis, the coherence evolution is enhanced significantly in that there is non-Markovian behavior for the dynamics of quantum coherence in a much larger range of scaled time for a giant atom than that for a small atom. Our study provide clues to preserve and to enhance quantum coherence in qutrit systems.

Design and Performance Analysis of Logic Circuits using FinFET Technology

As the dimensions of MOSFET (Metal Oxide Semiconductor Field Effect Transistor) decreases, the short channel effect (SCE) becomes a dominating concern in VLSI. The Short channel effect causes an exponential increase in the leakage current. To reduce the SCE and hence leakage current, a new technology has been developed in recent years. In this recent technology a 3D multiple gate MOSFETs like FinFET (Fin Field Effect Transistor) has been developed which possess numerous advantages over conventional MOSFETs and has attracted many engineers and designers. FinFET is the new growing technology that works in the nm range to minimize short channel effects. Many companies (like Intel) have started using FinFET technology. This document is a review paper of current research on FinFET technology and discusses how it can be used in future to design new logic devices (like Adder, Comparator, MUX and De-MUX etc.) and memory devices. Various parameters of FinFET like reduced short channel effects, less leakage current, low power consumption, less propagation delay and less time delay are discussed. Various mathematical models and software (HSpice) were used to simulate power, delay, power delay product, average power dissipation and energy delay product. Thus, FinFET technology was designed to eliminate the problem of SCE by permitting transistors to be scaled down into sub 20nm range.

Feynman–Kac formula for BSDEs with jumps and time delayed generators associated to path-dependent nonlinear Kolmogorov equations

We consider a system of forward backward stochastic differential equations (FBSDEs) with a time-delayed generator driven by Lévy-type noise. We establish a non-linear Feynman–Kac representation formula associating the solution given by the FBSDEs system to the solution of a path dependent nonlinear Kolmogorov equation with both delay and jumps. Obtained results are then applied to study a generalization of the so-called large investor problem, where the stock price evolves according to a jump-diffusion dynamic.

Differential convolutional network for noise mask estimation

With the advancements of speech synthesis technology, audio spoof detection systems have become vital for the security of automatic speaker verification systems. Many effective solutions have been offered for clean speech data. However, additive noise has a detrimental impact on the detection performance, as in many other speech related tasks. Noise mask is one of the methods proposed to increase the robustness against the additive noise. The purpose of the noise mask is to identify the time–frequency regions dominated by the noise signal. In this work, differential convolutional neural network is used to create noise masks. Differential convolution considers directional changes of the activations and generates new feature maps. Compared to the traditional convolutional network, a finer noise mask can be created with this method. Once the differential network for the noise masks is trained, its outputs are given to the spoof detection systems. Linear filterbank magnitudes are used as acoustic features for both noise masks and spoof detection. Therefore, the spoof detection systems have 2-channel inputs, i.e., linear filterbank magnitudes and its corresponding mask. Probabilistic linear discriminant analysis (PLDA) with x-vectors, emphasized channel attention, propagation and aggregation time delay neural network (ECAPA–TDNN), and light convolutional neural network (LCNN) followed by long short-term memory layers (LSTM) were used as classifiers. Three different noise types are used in both training and test stages, and two different noise types are used solely in the test stage, to stimulate seen and unseen conditions, respectively. Experiments conducted on the noisy version of ASVspoof 2015 challenge dataset showed that the LCNN–LSTM network with noise masks can achieve superior performance compared to other robust systems and can compete with the state-of-the-art. Considering the average of the known noise types, 2.67% equal error rate (EER) was observed. For the unknown noise types, 3.10% average EER was achieved. For the original (clean) ASVspoof 2015 data, the EER was 0.83%. Additionally, 2.6% EER was observed for logical access condition of ASVspoof 2019 data.