Start Time Research Articles

Efficiency of Foot and Ankle Surgeries Completed on the Preoperative Stretcher vs Operating Room Table: A Randomized Controlled Trial.

Extremity surgeons frequently operate on the preoperative stretcher rather than the operating room (OR) table. This study sought to identify differences between stretcher-based (SB) and OR table-based (TB) procedures with regard to time efficiency and OR team member preferences. We conducted a prospective randomized controlled trial comparing the efficiency of SB vs OR TB foot and ankle procedures. Fifty-two patients undergoing a hardware removal, isolated gastrocnemius recession, soft tissue procedure, or foreign body removal at our day surgery unit were included. Start time and exit time were recorded. "Start time" was the number of minutes between the patient entering the OR and first incision. "Exit time" was the number of minutes between the procedure ending and the patient exiting the OR. Surveys were disseminated to OR staff who participated in the included cases. The total measured time in the OR was an average 6 minutes shorter in the Stretcher group compared to the OR Table group (10 minutes vs 16 minutes, P < .001). SB procedures were associated with a significantly shorter start time (median difference = 4 minutes, P = .001), but not exit time (median difference = 1 minute, P = .058). No difference was found in actual surgical time. Thirty (96.8%) OR team members perceived SB procedures as enhancing OR efficiency, and 30 (96.8%) respondents considered SB procedures to be equal or superior to OR TB procedures in terms of patient safety. All would recommend or strongly recommend SB procedures. We found SB foot and ankle procedures to require less room time than OR TB procedures. Particularly for high-volume specialties, an average 6 minutes saved per case may meaningfully improve overall OR efficiency. Most OR team members believed that SB surgery improves OR efficiency and is the safer option for OR team members. Level II, randomized controlled trial, survey.

Timing Is Everything: Recognizing the Importance of Infusion Duration in Preoperative Antimicrobial Prophylaxis

Background: For preoperative antimicrobials to be most effective in preventing surgical site infection, they must be administered early enough to reach a minimum tissue concentration that is specific to each drug. However, antibiotics have widely ranging infusion durations, from intravenous push over a few minutes to slow infusion over two hours. Heterogeneity in recommended infusion administration instructions, importance of infusion completion prior to incision, and complexity of healthcare systems present just some of the barriers to achieving appropriate preoperative antibiotic prophylaxis. We compared the percentage of infusion completion prior to case start before and after a multidisciplinary intervention. Methods: We performed a retrospective analysis of all patients undergoing a colorectal surgical procedure as defined by the National Healthcare Safety Network at a single university hospital from 10/19/22-10/18/23. A recognition that some antimicrobials were not finished infusing prior to surgery start prompted a multidisciplinary group including antibiotic stewardship, colorectal surgery, perioperative nursing, and anesthesiology to create and deploy an order set shortening metronidazole infusion duration from 60 to 30 minutes and initiating infusion in the preoperative area instead of the operating room. No change to the cefazolin intravenous push over 3-5 minutes was made. Goal antimicrobial infusion was defined as completed infusion within 120 minutes prior to incision, and calculations were made based on infusion start time and case start times. Rate of infusion completion was compared from the pre-intervention period to a post-intervention period from 10/19/23 through the end of the year. Results: For all colorectal surgeries in the pre-intervention period, 95% (n=418/440) of cefazolin doses and 0.002% (n=1/427) doses of metronidazole met goal infusion timing. At-goal infusion timing increased to 99% (n=84/85) of cefazolin doses and 68% (n=56/82) of metronidazole doses in the post-intervention period, resulting in a statistically significant improvement for metronidazole (Fischer’s exact test p &lt; 0 .00001). The average time to metronidazole infusion completion changed from 45 minutes after procedure start to 58 minutes before procedure start. Conclusions: Multidisciplinary team engagement and deployment of an order set incorporating changes in duration and workflow for metronidazole infusion improved all antimicrobial preoperative infusions for colorectal procedures. Increased awareness of completing antimicrobial infusion prior to the incision may improve preoperative antimicrobial administration.Disclosure: Lindsay Donohue: Advisor - Abbvie

Development of an algorithm to detect feed bunk replacement events in growing cattle from feeding event data acquired by an electronic feed intake measurement system

Visual observations of competitive feeding behavior in cattle have been associated with animal productivity, health, and social hierarchy. However, human visual observations are time consuming, limiting the number of animals that can be evaluated. The objective of this study was to develop and assess an algorithm to detect disruptive feed bunk replacement events using feeding event data acquired from the Vytelle SENSE feed intake measurement system. Crossbred beef steers (N = 20) fed a grower diet were housed in one of two pens each equipped with three electronic feed bunks and a video recorder. A trained video observer recorded all feed bunk replacement events (when an actor animal displaced a reactor animal from the feed bunk and occupied the same feed bunk within a specified time interval, termed as the replacement criterion) and other agonistic activities at the feed bunk during a 4-d period. The Vytelle SENSE feed intake measurement system recorded the start and end timestamps of individual bunk visit (BV) events of animals. An algorithm was developed to determine replacement events based on the start and end times of consecutive BV events. Using video observation as the gold standard, the recall, precision, and F-score of the algorithm was calculated corresponding to time intervals from 1 to 60 s. The optimum replacement criterion was determined to be ≤ 18 s and ≤ 22 s for pens 1 and 2 respectively. The recall, precision, and F-score of the algorithm using these replacement criterions were high (> 0.75). A competition index was computed for each steer, calculated as the number of actor-initiated events divided by the number of actor and reactor events at the feed bunk. Spearman’s rank correlations (rs) between total visually observed agonistic interactions at the feed bunk and the replacement events detected from the electronic feeding event data using the algorithm and replacement criterion of the respective pen was determined. There were strong correlations (rs ≥ 0.71; P < 0.05) between the observed and electronic values for the number of actor and reactor events, and the competition index. These results demonstrate the potential to quantify disruptive feed bunk replacement events in confined beef cattle using electronically collected feeding event data from the Vytelle SENSE feed intake measurement system.

An Efficient Distributed Task Allocation Method for Maximizing Task Allocations of Multirobot Systems

This paper addresses the distributed task allocation problem for maximizing the total number of successfully executed tasks of multirobot systems. Due to the deadline time of tasks and fuel limits of robotic vehicles, not all tasks can be successfully executed sometimes. Based on the performance impact (PI) algorithm, an effective and efficient performance impact (EEPI) algorithm is proposed, its novelty lies in its cost function and task release procedure. The fundamental ideas of the proposed cost function are as follows. First, the traveling time from the initial position of each vehicle to the positions of its tasks is minimized, so that more time can be left for the vehicle to execute more tasks due to the limited fuel. Second, the start time of each task should be close enough to its deadline, so that tasks with earlier deadlines can be assigned earlier than those with later deadlines. To avoid invalid removal performance impacts (RPIs) and inclusion performance impacts (IPIs), the tasks assigned to a vehicle are all released if the number of tasks removed by the vehicle during the task removal phase is the most, which further increases the total number of successfully executed tasks. Both simulations and hardware-in-the-loop experiments suggest that compared with the state-of-the-art distributed task allocation algorithms, the proposed EEPI is not only effective in maximizing the number of successfully executed tasks but efficient in saving the number of iterations and time to converge. <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Note to Practitioners</i> —This work was motivated by the limitations of the existing distributed task allocation algorithms for maximizing the total number of successfully executed tasks. The consensus-based bundle algorithm (CBBA) has been proven to guarantee convergence and 50% optimality under the diminishing marginal gain (DMG) assumption in previously published works. Based on CBBA, a performance impact (PI) algorithm was proposed, and simulations show that it can assign more tasks than CBBA when applied to time-critical scenarios with low task-to-vehicle ratios. Starting from the results of PI, a rescheduling method named PI for maximizing assignments (PI-maxAss) was proposed, which has been demonstrated to assign more tasks than PI with high task-to-vehicle ratios. However, much more iterations and time are required by PI-maxAss to converge to globally consistent assignments because of the rescheduling. Due to the above considerations, an effective and efficient performance impact (EEPI) algorithm is proposed in this paper to maximize the number of successfully executed tasks without any rescheduling. Both simulations and hardware-in-the-loop experiments suggest that compared with the algorithms mentioned above, the proposed EEPI is effective in maximizing the number of successfully executed tasks and efficient in saving the number of iterations and time to converge. In future work, the distributed task allocation problem in which several vehicles execute a task at the same time cooperatively or a vehicle executes several tasks simultaneously will be further addressed.

Mechanism of enhanced boiling heat transfer by hydrophilic and hydrophobic hybrid deposited nanoparticles: A molecular dynamics simulation

The present work utilizes Molecular Dynamics (MD) method to study the physical mechanism of the effect of hybrid deposited nanoparticles (HDNs) on the boiling heat transfer by changing the wettability of the substrate. Three kinds of nanofluid simulation models are established, in which water molecules are used as the base fluid, and nanoparticles are hydrophilic deposited particles, hydrophobic deposited particles and HDNs, respectively. Compared with hydrophilic and hydrophobic deposited nanoparticles, it is found that the equilibrium contact angles of droplet containing HDNs decreases by 2.22° and 6.99° respectively during wetting simulation, indicating that HDNs improve the wettability of the substrate. By simulating the boiling process of three fluids, it is found that HDNs advance the start time of explosive boiling by 0.15 ns at most, that is, accelerate the nucleation time of bubbles, and increase the heat flux by 46.9 % at most, indicating that the heat convection near the substrate is enhanced. In addition, HDNs improve the vibration matching degree of atoms between the solid-liquid interface and enhance the heat transfer between the substrate and the fluid. The results of boiling simulation verify the conclusion that HDNs improve the wettability of the substrate and thus enhance the heat transfer inferred by droplet wetting simulation.

Study on the Transient Flow Characteristics of Multistage Centrifugal Pumps during the Startup Process before System Operation

Multistage pumps are essential in emergency water supply, irrigation, and other systems undergoing unavoidable hydraulic transitions like pump startup and valve operations. These transitions cause rapid changes in impeller speed, flow rate, and pressure, destabilizing the internal flow field and impacting system reliability. To study transient flow characteristics, a numerical analysis of a three-stage pump was conducted, focusing on vortex identification, entropy production, and time–frequency pressure pulsation. Using the SST turbulence model, the simulation analyzed different start times and flow rate variations. Findings revealed that shorter startup times intensified transient effects, with the head increasing rapidly initially and then stabilizing. Vortex structures showed periodic development and dissipation. Entropy production rose with impeller speed, peaking higher with shorter startups. Blade passing frequency dominated pressure pulsations, with increased low-frequency pulsations as speed rose. During valve opening, flow stabilization accelerated with increasing flow rates, reducing amplitude and eliminating low-frequency components. This research aids the reliable operation of high-pressure pumping systems in energy storage.

Bidirectional associations between the duration and timing of nocturnal sleep and daytime naps in adolescents differ from weekdays to weekends.

Previous studies examining bidirectional relationships between nocturnal sleep and napping have focused on sleep duration, leaving a gap in our understanding of how sleep timing contributes. Here, we assessed the duration and timing for night sleep and daytime naps, to evaluate how the previous night's sleep influences the next day's napping, and how napping influences same-night nocturnal sleep. We analyzed sleep diary and actigraphy data from 153 teens (males = 43.8%, mean age = 16.6 years). Participants who never napped were excluded. Nocturnal sleep-nap relationships were investigated using logistic and linear regression models separately for weekdays and weekends. Participants napped an average of 2.3 times a week. 167 school day naps and 107 weekends were recorded. Naps were on average 82.12 ± 53.34 minutes and the average nap onset was 14:58 ± 3.78 hours. Their duration, start and end times did not significantly differ between weekdays and weekends. Nocturnal sleep duration did not predict next-day nap occurrence or duration. However, on school days, earlier wake times significantly increased the likelihood of napping that day, and advanced nap timing. On weekends, later bedtimes and wake times delayed nap timing. On school days, napping longer than one's average shortened nocturnal sleep whereas on weekends, waking from a nap later than one's average delayed bedtimes. Early wake times increase the likelihood of napping and advance the time of a nap that day. Naps may be detrimental to the same night's sleep only if they are long and occur late, as these can delay bedtimes and shorten nocturnal sleep duration, especially on school days. The Cognitive and Metabolic Effects of Sleep Restriction in Adolescents (NFS4), https://clinicaltrials.gov/study/NCT03333512, ID: NCT03333512. Investigating Preferred Nap Schedules for Adolescents (NFS5), https://clinicaltrials.gov/study/NCT04044885, ID: NCT04044885.

Jointly modelling activity start time, travel mode, companionship, and destination location choices

Activity-travel decisions, including time use (i.e. activity start time), travel choices (i.e. mode and companionship), and destination location choices are interdependent and complex in nature. They are often controlled by observed factors such as sociodemographic, vehicle ownership, built environment, land use, and unobserved factors like attitude, preference, or habits which typically are not captured in the survey data. To accommodate these complex interactions and capture trade-offs among the time use-travel-land use choices, this study proposes a joint discrete choice model by introducing unobserved factors that are common to them. The model results confirm the presence of complex interdependencies among these choice dimensions. In addition, this study highlights the contribution of observed and unobserved factors introduced in the model by calculating the total variance of utility differences. Lastly, this study provides behavioural insights on the activity-travel patterns, which can be further used to develop robust travel demand management policies.

Optimal electric bus scheduling method under hybrid energy supply mode of photovoltaic-energy storage system-power grid

Currently, the charging energy of electric buses (EBs) primarily relies on the power grid (PG), and the production of the electricity for the power grid still results in carbon emissions. In recent years, a remarkable development has been observed in the photovoltaic (PV) technology. If EBs can be charged using electricity generated from PV, it has great potential to significantly reduce carbon emissions for EB systems at the source. Considering the inherent output power fluctuations from PV source, we propose a hybrid electricity supply mode named “Photovoltaic-Energy Storage System-Power Grid” (PV-ESS-PG). Firstly, considering the characteristics of different electricity supply modes, we introduce charging strategies tailored to different scenarios and formulate a cooperative optimization model for EB dispatching and charging plans. Secondly, we decompose this model into two sub-problems: bus dispatching and charging scheduling. To solve these two sub-problems, we employ the Non-dominated Sorting Genetic Algorithm-II (NSGA-II) to obtain the optimization results of bus dispatching plan, charging mode, charging start time, and charging duration. Finally, we validate the proposed method using real-world data of EB operation and PV output power. We further analyze the influences of weather conditions, ESS capacity, and EB rated battery capacity on the optimization results. We find that, compared to the conventional unitary power grid electricity supply mode, the proposed method reduces daily charging costs by 25.48% and carbon emissions by 68.71% of the whole bus route.

Initiation of adaptive feeding within 24 h after burn injury improves nutritional therapy for severely burned patients.

Nutritional therapy is a crucial component of treatment for severely burned patients. Although overly aggressive enteral nutrition immediately after burn injury has potential risks, nutritional disruption after a severe burn can also increase infection risk and delay wound healing. For approximately six decades, the Ruijin Hospital Burn Center has used two distinct approaches for patients during the early period after burn injury: complete fasting or adaptive feeding. Notably, adaptive feeding more closely resembles enteral nutrition. In this retrospective study, we analyzed factors influencing the selection of either modality, as well as the benefits of adaptive feeding. We sought to promote adaptive feeding as a precursor to initiating enteral nutrition. This retrospective study analyzed medical data from adult patients with extensive burns between January 2009 and December 2020. All patients had been admitted to the burn department within 24 h after injury and had a burned area comprising >30% of total body surface area. Patients were divided into two groups: adaptive feeding and fasting. We examined the total burned area, full-thickness burned area, burn type, inhalation injury, start time of adaptive feeding, and start time of enteral nutrition. Outcome measures were 28-day mortality and hospital mortality. Univariate analysis revealed significant differences in burn type, percent of total body surface area (TBSA), full-thickness burned area, and inhalation injury between the adaptive feeding and fasting groups (all p < 0.05). Linear regression analysis showed that full-thickness burned area and inhalation injury were the main factors influencing the start time of adaptive feeding in patients with severe burns (p < 0.05). After propensity score matching analysis, the results showed that the start time of enteral nutrition was significantly earlier in the adaptive feeding group (p < 0.01). However, overall mortality, 28-day mortality, and length of hospital stay did not significantly improve in the adaptive feeding group. The incidence of intolerance after enteral nutrition therapy did not significantly differ between groups. The results of the study showed that larger full-thickness burned areas and concomitant inhalation injury were the primary factors considered by physicians when selecting complete fasting for severely burned patients. Moreover, the results indicate that adaptive feeding improves nutritional therapy for severely burned patients by shortening the time between injury and initiation of enteral nutrition. Complete fasting due to concerns about extensive burned area and inhalation injuries does not reduce the incidence of enteral nutrition intolerance; instead, it delays the initiation of enteral nutrition.

Time-domain diffuse correlation spectroscopy at large source detector separation for cerebral blood flow recovery.

Time-domain diffuse correlation spectroscopy (td-DCS) enables the depth discrimination in tissue's blood flow recovery, considering the fraction of photons detected with higher time of flight (TOF) and longer pathlength through the tissue. However, the recovery result depends on factors such as the instrument response function (IRF), analyzed TOF gate start time, gate width and the source-detector separation (SDS). In this research we evaluate the performance of the td-DCS technique at three SDSs of 1.5, 2 and 2.5 cm to recover cerebral blood flow (CBF). To do that we presented comprehensive characterization of the td-DCS system through a series of phantom experiments. First by quality metrices such as coefficient of variation and contrast-to-noise ratios, we identified optimal time gate(s) of the TOF to extract dynamics of particles. Then using sensitivity metrices, each SDS ability to detect dynamics of particles in superficial and deeper layer was evaluated. Finally, td-DCS at each SDS was tested on healthy volunteers during cuff occlusion test and breathing tasks. According to phantom measurements, the sensitivity to estimate perfusion within the deep layer located at depth of 1.5 cm from the surface can be increased more than two times when the SDS increases from 1.5 cm to 2.5 cm.

Retrospective Analysis of Associated Costs and Sources of Variability in OR Utilization Across Weekdays.

Few studies have examined variability in OR utilization across weekdays. We conducted a retrospective analysis to determine OR utilization differences by day of the week and the source and financial effects of any variability. We extracted 55 months of data from a surgical data repository to calculate OR utilization, late starts, idle times, and delays for each weekday. Declines in OR utilization occurred as the week progressed and were attributed to compounding changes in late start, delay, and idle time. The average weekly cost for each OR associated with unused staffed minutes below a target OR utilization of 85% was $19,383, and the comparable lost weekly revenue was $60,256. Perioperative leaders should identify sources of OR utilization variability when developing strategies that enhance outcomes for patients, minimize costs, and maximize revenue.

Modelling of the conductor vaporization process for single-turn coil

Single-turn coil (STC) is a destructive pulsed magnet aiming at 100–300 T ultra high magnetic field. A conductor vaporization model is proposed for STCs. Using this model, the vaporization characteristics at different inner diameters and discharge currents are investigated. The results show that vaporization always starts from the inner surface of the conductor, but only from the interior of the conductor at higher current and smaller inner diameter. Moreover, the vaporization causes the electrical conductivity to decrease, leading the area with the highest current density to advance to the interior of the conductor. By comparison, the vaporization start time decreases as the current increases and the inner diameter decreases, and the vaporization start time at different diameters tends to coincide as current increases. The model in this study is validated by checking the consistency of the magnetic flux density at the central axis of STCs of the simulation results and the experimental data.

Does Timepoint of Surgical Procedure Affect the Outcome in Simultaneous Pancreas-Kidney Transplantation? A Retrospective Single-Center Analysis over 20 Years.

Background: Sleep deprivation and disturbances in circadian rhythms may hinder surgical performance and decision-making capabilities. Solid organ transplantations, which are technically demanding and often begin at uncertain times, frequently during nighttime hours, are particularly susceptible to these effects. This study aimed to assess how transplant operations conducted during daytime versus nighttime influence both patient and graft outcomes and function. Methods: simultaneous pancreas-kidney transplants (SPKTs) conducted at the University Hospital of Leipzig from 1998 to 2018 were reviewed retrospectively. The transplants were categorized based on whether they began during daytime hours (8 a.m. to 6 p.m.) or nighttime hours (6 p.m. to 8 a.m.). We analyzed the demographics of both donors and recipients, as well as primary outcomes, which included surgical complications, patient survival, and graft longevity. Results: In this research involving 105 patients, 43 SPKTs, accounting for 41%, took place in the daytime, while 62 transplants (59%) occurred at night. The characteristics of both donors and recipients were similar across the two groups. Further, the rate of (surgical) pancreas graft-related complications and reoperations (daytime 39.5% versus nighttime 33.9%; p = 0.552) were also not statistically significant between both groups. In this study, the five-year survival rate for patients was comparable for both daytime and nighttime surgeries, with 85.2% for daytime and 86% for nighttime procedures (p = 0.816). Similarly, the survival rates for pancreas grafts were 75% for daytime and 77% for nighttime operations (p = 0.912), and for kidney grafts, 76% during the day compared to 80% at night (p = 0.740), indicating no significant statistical difference between the two time periods. In a multivariable model, recipient BMI > 30 kg/m2, donor age, donor BMI, and cold ischemia time > 15 h were independent predictors for increased risk of (surgical) pancreas graft-related complications, whereas the timepoint of SPKT (daytime versus nighttime) did not have an impact. Conclusions: The findings from our retrospective analysis at a big single German transplant center indicate that SPKT is a reliable procedure, regardless of the start time. Additionally, our data revealed that patients undergoing nighttime transplants have no greater risk of surgical complications or inferior results concerning long-term survival of the patient and graft. However, due to the small number of cases evaluated, further studies are required to confirm these results.

Mixed-fleet operation of battery electric bus and hydrogen bus: Considering limited depot size with flexible refueling processes

Electrified transit is crucial for promoting zero-emission transportation in metropolitan cities. However, this initiative faces considerable challenges in Hong Kong due to limited space available for parking and refueling bus fleets. Despite the inexpensive operational costs of battery electric buses (BEBs), plenty of space is required to park and refuel BEBs. Hydrogen buses (HBs) can partially address the space issue with a longer driving range and shorter refueling time compared to the BEBs, whereas more operational costs must be spent. Therefore, a mixed fleet with BEB of HB tends to be a more cost-effective solution. In consideration of the distinctive characteristics of BEBs and HBs, this study develops an integrated vehicle scheduling and refueling of mixed fleets with multiple depots (IVSR-MFMD) restricted by the limited depot size (i.e., space provided for bus parking and bus refueling), where flexible refueling processes, allowing for uncertain refueling start times and refueling amounts, are endogenously incorporated into the operational cycle. The speed-up techniques are further used to reduce problem dimensions and reformulate the model. A two-route-two-depot example and a real-world case in Hong Kong are used to verify the model. The results demonstrate that adopting HB can efficiently reduce depot size and achieve lower operational costs when routes consume massive energy. Additionally, it is found that flexible refueling processes lead to lower operational costs, and the customized speed-up techniques can significantly improve computational efficiency.

A matheuristic-oriented iterated greedy algorithm for multi-mode resource-constrained project scheduling problem under uncertainty

Multi-mode resource-constrained project scheduling problem is one of the most important branches of combinatorial optimization problems. The aim is to find a feasible solution consisting of activity start time and execution mode so that the project makespan is minimized. However, there are a lot of uncertain events, that bring great challenges to project scheduling. We first propose a mixed integer linear programming model where the activity duration is uncertain. Then two uncertain parameters are introduced to describe the disturbance degree of uncertain activity duration and the allowable violation degree of constraints respectively, and the MILP model with uncertain activity duration is converted to its deterministic robust counterpart model. A matheuristic local optimization approach is proposed to balance computational time with the optimization of the computational result. A matheuristic-oriented iterated greedy algorithm that combines a matheuristic local optimization approach and an iterated greedy algorithm is proposed to solve this problem in this paper. Experimental results indicate that the robust counterpart model can obtain robust optimal solutions for small-scale instances in accepted computational time. Meanwhile, the proposed matheuristic-oriented iterated greedy algorithm can obtain robust near-optimal solutions for large-scale instances and is superior to other compared algorithms.

Domain knowledge-driven variational recurrent networks for drought monitoring

In the context of climate change, droughts, increasingly frequent and severe, necessitate effective monitoring. Existing methods, such as drought indices and data-driven models, face important limitations. Drought indices are built on prior expert knowledge but lack calibration based on actual drought events, while data-driven models prioritize goodness of fit over real event identification, undermining their credibility and generalization, and also struggling to generalize from regional to large-scale contexts. To address these challenges, here we introduce a hybrid machine learning framework for time series that combines domain knowledge and observational data in a variational recurrent neural network. The network models the joint distribution of total precipitation, air temperature, and real drought events, providing accurate predictions and uncertainty estimates. Extensive experiments focusing on a wide range of European drought events from 2011 to 2018 consistently show that our hybrid model surpasses both drought indices and data-driven models in terms of accuracy in drought detection, underlining its effectiveness, robustness, and stability. Our model achieves the best ROC-AUC (%) results in Afghanistan (79.7 ± 0.5), Italy (84.3 ± 0.6), Russia (89.4 ± 0.2), Europe-0 (84.3 ± 0.1), and Europe-1 (82.8 ± 0.4), effectively capturing the starting and ending times of drought events with lower uncertainty, and also generalizing better for unseen locations.

Arabic Diacritic-Aware Text-Audio Segmentation and Alignment Model (DASAM)

Abstract: This paper introduces the Diacritic-Aware Segmentation and Alignment Model for Arabic (DASAM). Diacritics are vital for pronunciation and meaning in the Arabic language but are often ignored by current speech recognition systems. DASAM is designed for word-level segmentation and alignment in unseen audio and associating them with diacritic-marked Arabic text. The DASAM approach uses linguistic analysis based on intonation rules. DASAM then applies Dynamic Time Warping (DTW) to match the reference audio word with its position in the unseen sentence audio. The model outputs a list of words with their start and end times in the recording. Tested on the Qur’an dataset, DASAM outperforms Google Speech-to-Text (STT) in predicting word timings. It achieves higher accuracy in text-audio alignment, with values of 0.959 and 0.957 for word start and end times, respectively (compared to Google STT’s 0.870 and 0.849). Additionally, DASAM employs advanced signal processing techniques and demonstrates robustness across various audio variations. These results establish that DASAM constitutes a fundamental building block for speech-to-text conversion and linguistic research in Arabic, particularly for applications involving diacritics.

Maneuver strategies of Starlink satellite based on SpaceX-released ephemeris

In the face of huge collision risks posed by the Starlink mega-constellation, the detection of unpredictable orbital maneuvers of Starlink satellites emerges as an important topic of Space Situational Awareness (SSA). The ephemerides released by the SpaceX company on the Space-track website provide a timely and valuable opportunity for addressing this problem. Based on the mean orbital elements extracted from Starlink ephemerides released at the end of 2023, the maneuver strategies, including maneuver frequency and characteristics of Starlink satellites in different orbital phases, are discussed, and the start time and end time with error ranges of confirmed maneuvers are acquired. It is found that operational satellites in Shell 1 perform an orbit maintenance maneuver approximately every 2 days, while those in Shells 2–5 execute a maneuver roughly once a day. Moreover, the parking satellites maneuver approximately every 0.25 days on average. As for satellites in the climbing orbit and the deorbiting orbit, they maneuver around every 0.1 days. The maneuver strategies of Starlink summarized in this paper can contribute to optimizing the observation plan of the Starlink constellation.

An improved ant colony optimization algorithm for two-sided U-type assembly line balancing problems

Aiming at the improvement of production system, a new method of two-sided U-type assembly line balance is proposed. Define the partition of a two-sided U-type assembly line and derive the formula for the task start time. The multi-objective model of two-sided U-type assembly line balance is established by minimizing a smoothing index, the number of positions and stations. Considering the dual influence of heuristic factors and pheromone information, the improved ant colony optimization algorithm is proposed. Combined with 37 examples, the improved ant colony optimization algorithm is used to solve the balancing problem of a two-sided straight line and a two-sided U-type assembly line, respectively. Compared with the results of other algorithms, it verifies that the model is reasonable and the improved ant colony optimization algorithm is effective. The balance effect of a two-sided U-type assembly line is better than that of a two-sided straight line, which means the length of the assembly line is shortened.