Search Results (2,143)

The detector array chips can be used to capture the transient space-time signal of the pulse radiation field. It is mainly composed of a photoelectric array detector and a readout circuit. However, the metal leads used to connect the detector and the readout circuit have long spacing. This can easily introduce additional delays, resulting in a decrease in the response performance of the chip, which cannot meet the goal of simultaneous transmission of ultra-fast detection signals. In recent years, the rapid development of three-dimensional interconnect technology has enabled the chip to achieve shorter interconnect spacing, smaller parasitic parameters and smaller delay time, thereby improving system response performance. The integrated detector array chips composed of three-dimensional interconnects has the advantages of fast signal interconnection transmission speed, high bandwidth, process compatibility and functional expansion compared with the traditional planar architecture. At the same time, there are some limitations and challenges. Therefore, this paper mainly reviews the evolution characteristics of the stacked architecture of the detector array chips, the process development and the nanosecond-level transmission integration challenges. This paper effectively incorporates the three into a unified framework. This provides a solution for the realization of integrated nanosecond detector array chips. Furthermore, it promotes the application and expansion of the chip in the pulse radiation field diagnosis technology. Full article

This paper formulates a latent HIV infection model with saturated immunity, two general infection rates (virus-to-cell and cell-to-cell transmission), and three time delays (infected cell activation delay, virus production delay, and immune response delay). The dynamical behaviors and equilibria stability of the model are theoretically analyzed. By constructing appropriate Lyapunov functions, sufficient conditions for the global asymptotic stability of the infection-free, immune-free, and coexistence equilibria are derived. All theoretical results are validated using numerical simulations. The simulation results reveal the difficulty of suppressing HIV infection for cases with a sufficiently large basic reproduction number. For patients with a high basic reproduction number, a single therapeutic strategy that only enhances the reversion rate of latently infected cells may not be effective. Full article

Accurate and reliable groundwater-level monitoring in deep observation wells remains difficult for conventional non-contact ultrasonic systems because narrow tubular geometries intensify multipath reflections, signal attenuation, and echo ambiguity. This study proposes a dual-signal direct time-of-flight (ToF) method that combines radiofrequency (RF) synchronization with one-way airborne ultrasonic propagation to a floating receiver located at the groundwater surface. In the proposed architecture, the RF signal provides a near-instantaneous time reference, whereas the ultrasonic signal defines the propagation delay, thereby eliminating dependence on echo-based ranging. The system integrates a wellhead surface unit for synchronized transmission and control, a floating unit for ToF acquisition and embedded processing, and an optional reference channel for in situ estimation of the effective sound speed. A duty-cycled power architecture is used to support low-power long-term deployment, while a multi-shot acquisition strategy with a median-like estimator improves robustness against startup transients, timing jitters, and false detections. Field validation was conducted over a 12-month period under actual groundwater-monitoring conditions, during which the groundwater depth varied between 14 m and 30 m below the wellhead datum. Within this field-validation interval, the proposed system achieved a mean absolute error of 0.048 m, a maximum absolute error of 0.050 m, and an overall valid detection rate of 99.4% over 358 valid cycles out of 360 scheduled cycles. In addition, a separate range-dependent confined-tubular propagation test was conducted to evaluate the extended detection capability of the RF-synchronized one-way ultrasonic ToF architecture. This test demonstrated stable acoustic-link ToF detection up to 300 m inside the tested 170 mm confined plastic pipeline. Therefore, the 300 m result should be interpreted as a range-dependent valid-detection result rather than as a 12-month groundwater-depth validation over the full 300 m interval. These results demonstrate that the proposed direct-ToF method provides an RF-synchronized one-way ultrasonic ToF framework with a floating receiver for groundwater-level monitoring in deep observation wells, while remaining compatible with low-power and IoT-based environmental monitoring systems. Full article

This paper proposes a cooled infrared focal plane circuit and detector imaging test system. The system features online acquisition, temperature monitoring, bias voltage programming, real-time imaging, and online testing capabilities, improving the testing and verification efficiency of infrared focal plane detector imaging systems. Temperature monitoring accuracy reaches ±0.02 K; bias voltage programming keeps bias noise below 100 nV/Hz^1/2; and a 2 × 2 pixel image array is used for data transmission, enabling algorithmic computation on pixel data for convenient image processing. Furthermore, this paper proposes various image algorithms and overall algorithm structures based on a single-chip pixel-level ADC, the dynamic range is 141.8 dB, and the maximum input charge capacity is 4.46 Ge⁻. The overall structure of the multifunctional image algorithm for infrared focal plane detectors is summarized, including background subtraction, blind pixel compensation, non-uniformity correction, windowing, pixel merging, spatial filtering, histogram equalization, and time delay integration (TDI). Non-uniformity is improved by 98.3%, blind pixel rate is reduced by 92.3%, background subtraction performance is improved by 93%, and spatial filtering and TDI improve relative spatial noise by 63% and 89%, respectively. Pixel merging can increase the gray mean by 4.09 times, enabling arbitrary windowing and uniform histogram distribution. These highly practical research efforts will drive the further development of future larger-array cooled infrared focal plane array (IRFPA) detector imaging test technology and more intelligent infrared image algorithms. Full article

This study examines the dynamic relationships among oil prices, monetary conditions, and nominal GDP growth in Saudi Arabia, with particular attention to short-run adjustment and long-run equilibrium patterns in an oil-dependent economy operating under a fixed exchange-rate regime. Rather than identifying structural monetary policy shocks, the study focuses on reduced-form dynamic associations between market-based monetary indicators, oil-price movements, and nominal economic activity. Using a high-frequency monthly dataset covering key macroeconomic variables, the analysis employs the Autoregressive Distributed Lag (ARDL) framework to estimate both short-run dynamics and long-run equilibrium relationships. An Error Correction Model (ECM) is used to capture the speed of adjustment toward equilibrium, while Granger causality tests assess short-term predictive linkages. The empirical results reveal that monetary indicators, particularly interest rates and money supply, exhibit lagged and non-monotonic associations with nominal GDP growth, reflecting delayed transmission under exchange-rate constraints. Oil-price movements emerge as a dominant driver, showing strong contemporaneous and lagged associations with growth, whereas inflation and exchange-rate movements display limited short-run predictive relevance. The ECM results indicate relatively rapid convergence toward long-run equilibrium, suggesting efficient adjustment dynamics. Granger causality findings further confirm the short-term predictive content of key macroeconomic variables. By integrating high-frequency data with ARDL–ECM estimation, VAR-based robustness checks, and sensitivity analysis, the study provides evidence on how oil-price movements, liquidity conditions, and interest-rate dynamics jointly shape growth fluctuations in Saudi Arabia. Full article

Three packaging methods were applied to fresh red apricots: P1 (plastic basket), P2 (breathable foam box), and P3 (perforated corrugated carton). To evaluate the effects of different packaging methods on apricot quality during simulated transportation and subsequent cold storage, fruit quality parameters were measured at 0 h, after 48 h of simulated vibration, and on days 3, 6, and 9 of cold storage. The results showed that, compared with P2 and P3, P1 more effectively maintained fruit surface color and firmness, delayed declines in soluble solids content (SSC), titratable acidity (TA), ascorbic acid content, and moisture content, and reduced water loss and overall weight loss. P1 also suppressed the increase in respiration rate, enhanced peroxidase (POD) and catalase (CAT) activities, suppressed increases in polyphenol oxidase (PPO) activity and hydrogen peroxide (H₂O₂) accumulation, and reduced lipid peroxidation. Additionally, P1 alleviated damage to the cell wall, maintained the structural integrity of the pulp cell walls, and improved the percentage of sound fruit. Transmission electron microscopy (TEM) confirmed that P1 delayed the degradation of the pulp cell wall and maintained the structural integrity of fruit cells. In conclusion, P1 (plastic basket) was the optimal packaging method for maintaining postharvest quality of fresh apricots during simulated transportation and cold storage. Full article

A quasi-continuous-wave (QCW) laser module based on a half-bridge structure is proposed for the low-voltage silicon photonics application, which forms a continuous-wave (CW) laser output when it equally distributes the heat dissipation into all lasers. Such a QCW laser module is modulated into a CW laser source for the chip-to-chip or board-to-board communication. The source current is alternatively diverted to the high-side and the low-side lasers by turning the corresponding gallium nitride high-electron-mobility transistor (GaN HEMT) on and off. The current redirection modulates multiple QCW laser outputs into a CW laser output; however, an undesirable laser downtime is produced during the transition time of the current redirection. Although for the 10 Gbps data rate transmission, a short laser downtime period may be scheduled for the time to perform either the laser steering task of the free-space optics (FSO) operation or the data pause for the fan-out delay, which is still preferred to be minimized for higher data rate transmission. The power efficiency and the laser downtime are functions of the parameters of the laser diodes, switch parasitic capacitances, input voltage, and the inductor. According to the mathematical derivation of the circuit response, the circuit design rules and the switching control strategy are provided to achieve high efficiency and low laser downtime. In the experiment, we implemented a laser module to achieve an FSO specification with a laser downtime of less than 3 ns, total harmonic distortion (THD) less than 10%, power efficiency greater than 60% and laser power higher than 1 W. Full article

Brucellosis remains a significant public health and economic burden in many regions, primarily transmitted from livestock to humans through direct contact and environmental contamination. In this paper, we develop a novel cross-species epidemic model that couples the transmission dynamics of brucellosis among sheep, humans, and the environmental reservoir of Brucella. The sheep population is divided into susceptible, exposed, infectious, and vaccinated compartments, while the human population is stratified into susceptible and infected classes. Environmental brucella load is explicitly modeled, and distributed time delays are incorporated to account for incubation periods and delayed exposure risks in humans. We prove that all solutions are non-negative and ultimately bounded, ensuring biological consistency. The basic reproduction number ${\mathcal{R}}_0$ is derived using the next-generation matrix method. Using Lyapunov functionals and LaSalle’s invariance principle, we establish that the disease-free equilibrium is globally asymptotically stable when ${\mathcal{R}}_0\le 1$, whereas a unique endemic equilibrium exists and is globally asymptotically stable when ${\mathcal{R}}_0>1$. Sensitivity analysis identifies the environmental transmission rate, shedding rate, and disinfection as the most influential parameters. Treatment efficacy is shown to exhibit a critical threshold $p^{\mathrm{cr}}=1-1/{\mathcal{R}}_0$, above which eradication becomes feasible. Numerical simulations validate the theoretical findings and demonstrate that time delays affect outbreak timing but not asymptotic stability. These results provide quantitative guidance for brucellosis control strategies, emphasizing environmental sanitation, culling, and vaccination as key interventions. Full article

In complex wellbore environments, traditional ball-drop, cable, and electromagnetic sliding sleeve communication methods face reliability problems caused by high temperature, high pressure, complex trajectories, and signal attenuation. This paper presents a pressure-wave-based downhole communication and sliding sleeve activation system. Surface pressure variations generated by pump displacement and pressure relief are used to transmit encoded commands through the wellbore fluid and realize non-contact activation of the downhole sliding sleeve. A wellbore pressure-wave propagation model is established, and the effects of well depth, wellbore diameter, pump displacement, pump-on time, pressure-relief timing, and pressure-relief duration on bottom-hole pressure response are analyzed. A bipolar non-return-to-zero coding strategy combined with a constant-threshold decoding method is proposed to improve signal recognizability and robustness. Simulation results show that for a 5000 m wellbore and a pressure-wave velocity of 1100–1300 m/s, the signal transmission delay is approximately 4.2 s, and the bottom-hole pressure responses induced by pump displacement and pressure-relief valve operation can be clearly distinguished. Laboratory tests at 150 °C and 120 MPa showed that the sliding sleeve achieved a 110 mm stroke and 100% opening ratio in four repeated activation tests. In the field test, three pressure command cycles between 10 MPa and 40 MPa successfully triggered the sliding sleeve, followed by a squeeze test with a displacement of 0.3–0.7 m³/min and a maximum pressure of approximately 60 MPa. The results demonstrate that the proposed system provides a feasible and reliable pressure-wave communication method for downhole sliding sleeve activation in deep and long horizontal wells. Full article

Controller Area Network (CAN) remains a key in-vehicle communication protocol for distributed automotive control systems, where predictable communication timing is essential for coordinated operation of electronic control units (ECUs). This paper presents a cross-validated framework for timing analysis of automotive CAN networks by combining Deterministic and Stochastic Petri net (DSPN) modeling with worst-case response-time (WCRT) analysis. A DSPN model is developed to represent CAN message generation, priority-based arbitration, bus access, and non-preemptive frame transmission. The model is implemented in TimeNet to evaluate bus utilization, queue occupancy, and access-delay behavior under representative automotive traffic. In parallel, analytical WCRT equations are used to derive conservative latency bounds for each message class. The proposed framework links stochastic performance observations from DSPN simulation with deterministic schedulability guarantees from WCRT analysis, enabling consistency checks between average-case and worst-case timing results. A case study based on a 500 kbit/s automotive CAN configuration with six priority classes is presented. The results show that the network operates at approximately 35.9% bus utilization and that all message classes satisfy their timing requirements with a substantial margin, with the maximum worst-case response time remaining below 2 ms. The study further discusses the modeling assumptions, abstraction limits, and sensitivity of timing behavior to frame length and traffic configuration. The proposed framework provides a practical methodology for timing-oriented design and early-stage validation of automotive CAN communication systems. Full article

Extracting hydrocarbons from complex, ultra-deepwater and high-pressure/high-temperature wells requires precise control of hydrostatic pressure to avoid well control problems. Among these, a gas kick is one of the most serious events, as it can quickly develop into a blowout with severe consequences for both safety and project cost. Traditionally, the industry has depended on reactive surface-based indicators, such as pit volume and delta flow, for early kick detection (EKD). However, these methods are often limited by data transmission delays and frequent false alarms. This review goes beyond a conventional summary by critically examining the key weaknesses of current EKD technologies. In particular, it highlights major challenges in modern sensor systems, including the difficulty of interpreting ultrasonic signals in multiphase flow and the way formation leakage can hide or distort kick indicators. It also provides a detailed and original link between specific Artificial Intelligence (AI) models and the drilling signals they are designed to analyze. Although recent studies have shown progress in downhole sensing and predictive algorithms, a significant gap still exists between theoretical models and the highly dynamic, multiphase conditions found in real wellbores. This makes it necessary to evaluate EKD technologies considering actual field demands rather than idealized assumptions. To address these limitations, this review proposes several practical directions for future work. These include the development of dynamic, multiphase, acoustic computational fluid dynamics (CFD) models to improve ultrasonic signal interpretation, the standardization of unsupervised AI models supported by synthetic data generation, the integration of unified leakage detection frameworks, the mechanical standardization of Managed Pressure Drilling (MPD) systems, and the adoption of rig-based edge computing to enable faster and more reliable real-time decision-making. Full article

Dense Long Range (LoRa) networks suffer from packet loss when many end devices contend for the same unlicensed channel. Channel activity detection (CAD) can miss weak or cross-spreading-factor (cross-SF) transmissions, while a uniform carrier sense multiple access with collision avoidance (CSMA/CA) backoff rule ignores the different time-on-air (ToA) costs of SF7–SF12 packets. To address these two coupled problems, this paper proposes an interference-limit-aware CSMA protocol (ILA-CSMA). ILA-CSMA first combines CAD with an instantaneous received signal strength indicator (RSSI) test derived from the residual interference tolerance of the selected spreading factor, and then scales the contention window according to normalized ToA. The protocol is implemented in the Framework for LoRa (FLoRa), an OMNeT++-based LoRa network simulator, and is evaluated for networks with 100–2000 nodes. Compared with Pure ALOHA, Slotted ALOHA, standard CSMA/CA, and two ablation variants, ILA-CSMA improves dense-network access by jointly reducing hidden collisions and airtime imbalance. In the 2000-node case, it increases the packet delivery ratio (PDR) by about 20 percentage points relative to standard CSMA/CA, keeps the Jain fairness index (JFI) above the 0.85 reference line, reduces the energy consumed per successful packet to 22% of the standard CSMA/CA value, and reduces conditional average packet delay from 18.5 s to 8.2 s. These results show that interference-aware sensing and ToA-aware backoff can improve large-scale LoRa access under the evaluated simulation conditions. Full article

The continuous growth of IIoT systems has significantly increased the number of connected devices and message interactions, creating higher requirements for communication mechanisms in terms of scalability and adaptability under dynamic network environments. Although MQTT is widely used for its lightweight communication, its traditional centralized broker architecture limits scalability and fault tolerance in large-scale data transmission, reducing system scalability and fault tolerance. Additionally, static QoS configuration is difficult to adapt to dynamic environmental changes, resulting in high end-to-end latency and limited system throughput. To address these issues, this paper proposes a distributed MQTT communication method based on intelligent QoS routing and hierarchical collaboration (DAIS-MQTT). This method designs a network routing algorithm based on a hierarchical tree structure (LCN), which effectively addresses the scalability limitation of centralized proxies by enabling multi-level proxy collaboration and self-recovery from faults. At the same time, it proposes a QoS routing algorithm based on intelligent decision trees (IQR), which jointly optimizes proxy selection and QoS levels to dynamically adapt to changes in the network environment, thereby solving the problem of insufficient adaptability in static QoS configurations. Experimental results show that compared with the traditional MQTT-based communication method, the DAIS-MQTT method reduces the average message delay by 29.9%, increases system throughput by 28.2%, and maintains a reliable transmission rate of 98.7% in unreliable network environments, making it suitable for high-dynamic and large-scale IIoT communication scenarios. Full article

Background/Objectives: Ventriculoperitoneal shunt (VPS) placement alters cerebrospinal (CSF) dynamics and has been associated with hearing changes through pressure transmission via the cochlear aqueduct. Despite the large number of patients undergoing VPS placement annually, associated hearing changes remain poorly characterized. This scoping review aimed to characterize the available evidence on hearing outcomes following VPS placement and identify gaps warranting further investigation. Methods: This scoping review was conducted in accordance with PRISMA-ScR guidelines. PubMed was queried from January 1980 through January 2026. Eligible studies included case reports, case series, and observational cohorts reporting hearing outcomes following VPS placement. Two independent reviewers screened titles, abstracts, and full texts. Risk of bias was assessed using Joanna Briggs critical appraisal tools. Due to heterogeneity in study designs, outcomes metrics, and follow-up duration, quantitative synthesis was not performed. Results: Nineteen studies comprising approximately 200 patients met inclusion criteria. Hearing deterioration and improvement were each reported in 7 studies (36.8%); mixed outcomes were reported in 5 studies (26.3%). Acute hearing changes occurred within 48 h in 3 studies (15.8%), whereas delayed changes were described in 13 studies (68.4%). Overall quality of evidence was low. Conclusions: This scoping review identifies VPS placement as a clinically underrecognized contributor to hearing change. Current evidence is heterogenous and dominated by low level studies, underscoring the need for prospective investigation with standardized audiologic protocols. Preoperative audiograms should be considered when possible, as well as a low threshold for audiology referral for postoperative hearing concerns. Full article

Time-varying delay and limited communication resources pose two fundamental challenges to the stability and efficiency of discrete-time cascade control systems (CCS). To address these issues, this paper presents, for the first time, the co-design of an event-triggered PI–P controller for discrete-time CCS with time-varying delay. A discrete-time state-space model with time-varying state delay is first established to accurately characterize the cascade dynamics. An event-triggered mechanism (ETM) is then introduced to effectively reduce redundant data transmissions while maintaining desired control performance. Based on Lyapunov stability theory, sufficient conditions are derived to enable the joint synthesis of the primary Proportional (P) controller, the secondary Proportional–Integral (PI) controller, and the event-triggering thresholds in an integrated manner. Simulation results confirm that the proposed method delivers improved transient performance and steady-state accuracy while reducing control update frequency, thereby providing a superior balance between control performance and communication efficiency compared with conventional event-triggered P–P cascade control strategies. Overall, the proposed co-design framework offers an effective and systematic solution for both enhancing stability and reducing unnecessary control updates in discrete-time CCS subject to time-varying delay. Full article