The effect of the crust on the estimation of mantle Q from spectral ratios of multiple ScS phases

1997 ◽  
Vol 87 (3) ◽  
pp. 778-781
Author(s):  
Takehi Isse ◽  
Ichiro Nakanishi
Keyword(s):  
Background Noise ◽  
Numerical Experiments ◽  
Time Window ◽  
Time Windows ◽  
Specific Time ◽  
Spectral Ratios ◽  
Arrival Times ◽  
Numerical Tests ◽  
Error Bars ◽  
The Difference

Abstract To estimate Qscs, previous studies used the spectral ratios of multiple ScS phases calculated for specific time windows. They assumed that the spectral ratios had linear relation with frequency. However, the spectral ratios very often did not seem to be linear, and the error bars were very large for frequencies higher than about 0.05 Hz. We have performed numerical experiments to search for the cause of these anomalies and found that they are caused by the multiple reflection in the crust under the surface bounce point of ScS2. A method of suppressing the anomalies is to start the time of the time window at 40 sec prior to the theoretical arrival times of the multiple ScS phases. In numerical tests, the difference between the correct and estimated values of Qscs is only 0 to 5% using this method, but it is 10 to 50% in the conventional method. We find that the crustal effect is more important in the estimation of Qscs than background noise, which has been readily handled in previous studies using standard stacking techniques.

No Specific Time Window Distinguishes between Community-, Healthcare-, and Hospital-Acquired Bacteremia, but They Are Prognostically Robust

2014 ◽  
Vol 35 (12) ◽  
pp. 1474-1482 ◽  
Author(s):  
Kim Oren Gradel ◽  
Stig Lønberg Nielsen ◽  
Court Pedersen ◽  
Jenny Dahl Knudsen ◽  
Christian Østergaard ◽  
...  
Keyword(s):  
Roc Curve ◽  
Operating Characteristic ◽  
Time Window ◽  
Time Windows ◽  
Population Based ◽  
Prognostic Models ◽  
Specific Time ◽  
Sharp Transition ◽  
Community Healthcare ◽  
Hospital Acquired

Objective.We examined whether specific time windows after hospital admission reflected a sharp transition between community and hospital acquisition of bacteremia. We further examined whether different time windows to distinguish between community acquisition, healthcare association (HCA), and hospital acquisition influenced the results of prognostic models.Design.Population-based cohort study.Setting.Hospitals in 3 areas of Denmark (2.3 million inhabitants) during 2000–2011.Methods.We computed graphs depicting proportions of males, absence of comorbidity, microorganisms, and 30-day mortality pertaining to bacteremia 0, 1, 2, …, 30, and 31 days and later after admission. Next, we assessed whether different admission (0–1, 0–2, 0–3, 0–7 days) and HCA (30, 90 days) time windows were associated with changes in odds ratio (OR) and area under the receiver operating characteristic (ROC) curve for 30-day mortality, adjusting for sex, age, comorbidity, and microorganisms.Results.For 56,606 bacteremic episodes, no sharp transitions were detected on a specific day after admission. Among the 8 combined time windows, ORs for 30-day mortality varied from 1.30 (95% confidence interval [CI], 1.23–1.37) to 1.99 (95% CI, 1.48–2.67) for HCA and from 1.36 (95% CI, 1.24–1.50) to 2.53 (95% CI, 2.01–3.20) for hospital acquisition compared with community acquisition. Area under the ROC curve changed marginally from 0.684 (95% CI, 0.679–0.689) to 0.700 (95% CI, 0.695–0.705).Conclusions.No time transitions unanimously distinguished between community and hospital acquisition with regard to sex, comorbidity, or microorganisms, and no difference in 30-day mortality was seen for HCA patients in relation to a 30- or 90-day time window. ORs decreased consistently in the order of hospital acquisition, HCA, and community acquisition, regardless of time window combination, and differences in area under the ROC curve were immaterial.

scholarly journals Serotonin Signals Modulate Mushroom Body Output Neurons for Sustaining Water-Reward Long-Term Memory in Drosophila

2021 ◽  
Vol 9 ◽  
Author(s):  
Wang-Pao Lee ◽  
Meng-Hsuan Chiang ◽  
Li-Yun Chang ◽  
Wei-Huan Shyu ◽  
Tai-Hsiang Chiu ◽  
...  
Keyword(s):  
Mushroom Body ◽  
Molecular Mechanisms ◽  
Time Window ◽  
Time Windows ◽  
Long Term Memory ◽  
Specific Time ◽  
Water Reward ◽  
Term Memory ◽  
Output Neurons

Memory consolidation is a time-dependent process through which an unstable learned experience is transformed into a stable long-term memory; however, the circuit and molecular mechanisms underlying this process are poorly understood. The Drosophila mushroom body (MB) is a huge brain neuropil that plays a crucial role in olfactory memory. The MB neurons can be generally classified into three subsets: γ, αβ, and α′β′. Here, we report that water-reward long-term memory (wLTM) consolidation requires activity from α′β′-related mushroom body output neurons (MBONs) in a specific time window. wLTM consolidation requires neurotransmission in MBON-γ3β′1 during the 0–2 h period after training, and neurotransmission in MBON-α′2 is required during the 2–4 h period after training. Moreover, neurotransmission in MBON-α′1α′3 is required during the 0–4 h period after training. Intriguingly, blocking neurotransmission during consolidation or inhibiting serotonin biosynthesis in serotoninergic dorsal paired medial (DPM) neurons also disrupted the wLTM, suggesting that wLTM consolidation requires serotonin signals from DPM neurons. The GFP Reconstitution Across Synaptic Partners (GRASP) data showed the connectivity between DPM neurons and MBON-γ3β′1, MBON-α′2, and MBON-α′1α′3, and RNAi-mediated silencing of serotonin receptors in MBON-γ3β′1, MBON-α′2, or MBON-α′1α′3 disrupted wLTM. Taken together, our results suggest that serotonin released from DPM neurons modulates neuronal activity in MBON-γ3β′1, MBON-α′2, and MBON-α′1α′3 at specific time windows, which is critical for the consolidation of wLTM in Drosophila.

scholarly journals Research on Aircraft Surface Taxi Path Planning and Conflict Detection and Resolution

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Ningning Zhao ◽  
Nan Li ◽  
Yu Sun ◽  
Lei Zhang
Keyword(s):  
Time Window ◽  
Time Windows ◽  
Conflict Detection ◽  
Real Time Control ◽  
A Algorithm ◽  
Use Of Time ◽  
Time Control ◽  
Control Decision ◽  
The Difference ◽  
Glide Paths

Aircraft surface taxiing conflict avoidance is mostly adopted by waiting and rerouting methods, but this method does not consider the difference in total taxiing time that may be caused by different strategies. In this study, the airport taxiing path optimization model and taxiing area division model are constructed first. Then, the taxiway use is controlled by subregion based on the analysis of the surface activity area connection relationship. Based on the results of aircraft surface taxiway preselection, the time window of the taxiing area is solved and conflict detection is performed. For aircraft with taxiing conflicts, waiting or changing paths is selected to deconflict taxiing by comparing priorities. An improved A∗ algorithm solution is applied to generate conflict-free glide paths and new glide trajectory occupancy time windows, while the glide paths of aircraft without glide conflicts are not affected. The results of the study show that the use of time windows for conflict detection and deconfliction can further reduce the total taxiing time of aircraft operating on the surface, resulting in a significant reduction in the number of aircraft conflicts, and thus, airport operational safety is ensured. This study has a high practical value and is expected to be applied in the real-time control decision of aircraft taxiing in the future.

Seismic attenuation analysis in the central part of the Leipzig-Regensburg fault zone using the Multiple Lapse Time Window Analysis and Qopen

2021 ◽  
Author(s):  
Marcel van Laaten ◽  
Tom Eulenfeld ◽  
Ulrich Wegler
Keyword(s):  
Fault Zone ◽  
Time Window ◽  
Time Windows ◽  
Seismic Attenuation ◽  
Forward Modelling ◽  
Frequency Range ◽  
Lapse Time ◽  
Intrinsic Attenuation ◽  
Error Bars ◽  
Attenuation Values

<p>Seismic attenuation provides valuable information about the structure of the crust. For the analysis of seismic attenuation in the central part of the Leipzig-Regensburg fault zone in Germany, where numerous areas of intracontinental earthquake swarms are located, we use 18 of the region's strongest earthquakes from the period 2008 to 2019 with a magnitude between 1.4 and 3.0 in the frequency range between 3 and 34 Hz. Two different methods were used to determine the frequency-dependent scattering and the intrinsic attenuation on one hand and to compare the two methods with respect to their results on the other hand. Both methods, the Multiple Lapse Time Windows Analysis (MLTWA) and the Qopen method use the acoustic radiative transfer theory for forward modelling to generate synthetic data and fit them to the observed data. As a by-product of Qopen, we also obtain the energy site amplifications of the stations used in the inversion, as well as the estimated moment magnitudes of the inverted earthquakes. In addition, factors that influence the inversion were investigated. Different combinations of inversion parameters were tested for the MLTWA, as well as the influence of the window length on the result of Qopen. The results from both methods provide similar results within their error bars, with intrinsic attenuation being stronger than scattering and overall, rather low attenuation values compared to other regions.</p>

scholarly journals Optimization of Port Emergency Materials Dispatch with Time Windows Constraints under Uncertainties

2021 ◽  
Vol 2021 ◽  
pp. 1-19
Author(s):  
Bowei Xu ◽  
Yuqing Wang ◽  
Junjun Li
Keyword(s):  
Genetic Algorithm ◽  
Numerical Experiments ◽  
Time Window ◽  
Time Windows ◽  
Bilevel Optimization ◽  
Container Terminals ◽  
Adaptive Genetic Algorithm ◽  
Short Term ◽  
Total Cost ◽  
Logistic Mapping

Uncertainties exist and affect the actual port production. For example, at the beginning of 2020, the sudden outbreak of COVID-19 seriously affected terminal production and increased the short-term pressure of handling at container terminals. Consequently, a large number of containers were stacked at terminals, and the problem of terminal congestion became more serious. To solve the congestion problem of container terminals and ensure the priority dispatch of emergency materials, this study uses the optimized arrival patterns of external trucks and a priority dispatch strategy for emergency materials to establish a bilevel optimization model for container terminals and proposes a chaotic genetic algorithm based on logistic mapping as a solution. Through numerical experiments, the algorithm proposed in this study was compared with the genetic algorithm and adaptive genetic algorithm. The experimental results show that the model and algorithm proposed in this study can effectively reduce the total cost of containers in a terminal while ensuring the priority dispatch of emergency materials, reducing the overlapping part of the time window, optimizing the arrival mode of external trucks, and reducing the waiting time of external trucks, effectively alleviating the terminal congestion problem.

scholarly journals A hybrid ant colony algorithm based on multiple strategies for the vehicle routing problem with time windows

2021 ◽  
Author(s):  
Hongguang Wu ◽  
Yuelin Gao ◽  
Wanting Wang ◽  
Ziyu Zhang
Keyword(s):  
Vehicle Routing ◽  
Vehicle Routing Problem ◽  
Ant Colony Algorithm ◽  
Time Window ◽  
Time Windows ◽  
Ant Colony ◽  
Routing Problem ◽  
Multiple Strategies ◽  
Hard Time ◽  
Mutation Operation

AbstractIn this paper, we propose a vehicle routing problem with time windows (TWVRP). In this problem, we consider a hard time constraint that the fleet can only serve customers within a specific time window. To solve this problem, a hybrid ant colony (HACO) algorithm is proposed based on ant colony algorithm and mutation operation. The HACO algorithm proposed has three innovations: the first is to update pheromones with a new method; the second is the introduction of adaptive parameters; and the third is to add the mutation operation. A famous Solomon instance is used to evaluate the performance of the proposed algorithm. Experimental results show that HACO algorithm is effective against solving the problem of vehicle routing with time windows. Besides, the proposed algorithm also has practical implications for vehicle routing problem and the results show that it is applicable and effective in practical problems.

scholarly journals The last-mile vehicle routing problem with delivery options

OR Spectrum ◽  
2021 ◽  
Author(s):  
Christian Tilk ◽  
Katharina Olkis ◽  
Stefan Irnich
Keyword(s):  
Vehicle Routing ◽  
Vehicle Routing Problem ◽  
Resource Constraints ◽  
Time Window ◽  
Time Windows ◽  
Service Level ◽  
Optimal Solutions ◽  
Routing Problem ◽  
Common Location ◽  
Delivery Options

AbstractThe ongoing rise in e-commerce comes along with an increasing number of first-time delivery failures due to the absence of the customer at the delivery location. Failed deliveries result in rework which in turn has a large impact on the carriers’ delivery cost. In the classical vehicle routing problem (VRP) with time windows, each customer request has only one location and one time window describing where and when shipments need to be delivered. In contrast, we introduce and analyze the vehicle routing problem with delivery options (VRPDO), in which some requests can be shipped to alternative locations with possibly different time windows. Furthermore, customers may prefer some delivery options. The carrier must then select, for each request, one delivery option such that the carriers’ overall cost is minimized and a given service level regarding customer preferences is achieved. Moreover, when delivery options share a common location, e.g., a locker, capacities must be respected when assigning shipments. To solve the VRPDO exactly, we present a new branch-price-and-cut algorithm. The associated pricing subproblem is a shortest-path problem with resource constraints that we solve with a bidirectional labeling algorithm on an auxiliary network. We focus on the comparison of two alternative modeling approaches for the auxiliary network and present optimal solutions for instances with up to 100 delivery options. Moreover, we provide 17 new optimal solutions for the benchmark set for the VRP with roaming delivery locations.

scholarly journals Impact of COVID-19 pandemic on HIV viremia: a single-center cohort study in northern Italy

2021 ◽  
Vol 18 (1) ◽  
Author(s):  
Ilaria Izzo ◽  
Canio Carriero ◽  
Giulia Gardini ◽  
Benedetta Fumarola ◽  
Erika Chiari ◽  
...  
Keyword(s):  
Time Window ◽  
Time Windows ◽  
Continuum Of Care ◽  
Northern Italy ◽  
Hiv Diagnosis ◽  
Hiv Patients ◽  
Before And After ◽  
Missed Visits ◽  
Hiv Continuum Of Care ◽  
The Impact

Abstract Background Brescia Province, northern Italy, was one of the worst epicenters of the COVID-19 pandemic. The division of infectious diseases of ASST (Azienda Socio Sanitaria Territoriale) Spedali Civili Hospital of Brescia had to face a great number of inpatients with severe COVID-19 infection and to ensure the continuum of care for almost 4000 outpatients with HIV infection actively followed by us. In a recent manuscript we described the impact of the pandemic on continuum of care in our HIV cohort expressed as number of missed visits, number of new HIV diagnosis, drop in ART (antiretroviral therapy) dispensation and number of hospitalized HIV patients due to SARS-CoV-2 infection. In this short communication, we completed the previous article with data of HIV plasmatic viremia of the same cohort before and during pandemic. Methods We considered all HIV-patients in stable ART for at least 6 months and with at least 1 available HIV viremia in the time window March 01–November 30, 2019, and another group of HIV patients with the same two requisites but in different time windows of the COVID-19 period (March 01–May 31, 2020, and June 01–November 30, 2020). For patients with positive viremia (PV) during COVID-19 period, we reported also the values of viral load (VL) just before and after PV. Results: the percentage of patients with PV during COVID-19 period was lower than the previous year (2.8% vs 7%). Only 1% of our outpatients surely suffered from pandemic in term of loss of previous viral suppression. Conclusions Our efforts to limit the impact of pandemic on our HIV outpatients were effective to ensure HIV continuum of care.

Study on Vehicle Logistics Routing Path Problem with Time Windows Based on Particle Swarm Optimization

2014 ◽  
Vol 687-691 ◽  
pp. 5161-5164
Author(s):  
Lian Zhou Gao
Keyword(s):  
Particle Swarm Optimization ◽  
World Economy ◽  
Time Window ◽  
Time Windows ◽  
Particle Swarm ◽  
Modern Logistics ◽  
Swarm Optimization ◽  
Logistics Industry ◽  
Search Speed ◽  
Simulation Results

As the development of world economy, how to realize the reasonable vehicle logistics routing path problem with time window constrain is the key issue in promoting the prosperity and development of modern logistics industry. Through the research of vehicle logistics routing path 's demand, particle swarm optimization with a novel particle presentation is designed to solve the problem which is improved, effective and adept to the normal vehicle logistics routing. The simulation results of example indicate that the algorithm has more search speed and stronger optimization ability.

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