Travel Patterns of Frequent and Non-Frequent Users on I-66 High-Occupancy Toll Lanes and Implications for the Value of Time Estimation

2021 ◽  
pp. 036119812110041
Author(s):  
Mecit Cetin ◽  
Shanjiang Zhu ◽  
Hong Yang ◽  
Olcay Sahin
Keyword(s):  
Travel Time ◽  
Value Of Time ◽  
Time Saving ◽  
Peak Period ◽  
Data Set ◽  
Frequent Users ◽  
Depth Analysis ◽  
The Mean ◽  
High Occupancy Toll ◽  
Express Lanes

Based on a three-month toll transaction data set that includes an anonymized unique identifier for each vehicle, this paper presents an in-depth analysis of traffic volumes and tolls on the I-66 High-Occupancy Toll (HOT) express lanes in Northern Virginia. The unique identifiers allow quantification of how frequently each vehicle travels through the corridor. Vehicles observed in selected time intervals are categorized into frequent and non-frequent groups based on the total number of trips made by each vehicle. For the morning commute, the analyses show that those traveling frequently on the HOT lanes are more sensitive to high tolls and typically travel earlier in the morning to avoid higher tolls. In other words, when tolls are relatively high (e.g., over $20), the fraction of frequent users in the traffic is much smaller as compared with that of non-frequent users (e.g., 25% versus 75%). To estimate how much toll the HOT-lane users are paying per unit of travel time saved, that is, value of travel time saving (VTTS), speeds on alternative routes parallel to the I-66 corridor are computed from probe data and compared with those on I-66 express lanes. The results show that the mean VTTS is $45.37 and $61.78 for frequent and non-frequent users, respectively, during the morning peak period. Whereas for the afternoon peak, the mean VTTS is $38.14 and $37.64 for frequent and non-frequent users. The implications of the difference in these value of time distributions for dynamic tolling are discussed.

Replication of Daily and Monthly Freeway Demand Variations for Travel Time Reliability Procedures

2020 ◽  
Vol 2674 (9) ◽  
pp. 727-741
Author(s):  
Amjad Dehman ◽  
Tom Brijs ◽  
Alexander Drakopoulos
Keyword(s):  
Travel Time ◽  
Reliability Assessment ◽  
Reliability Estimation ◽  
Assessment Procedure ◽  
Travel Time Reliability ◽  
Peak Period ◽  
Traffic Demand ◽  
Time Index ◽  
The Mean ◽  
Demand Variation

The sixth edition of the Highway Capacity Manual (HCM) incorporates a travel time reliability assessment procedure for freeways and urban streets. Several demand adjustment factors, referred to by demand multipliers, are used to capture traffic demand variation across different days and months. These factors are currently produced by referencing the average daily traffic volume of each day-month combination to a base daily volume. However, practitioners usually perform traffic analyses during specific times of the day, for example, peak periods, off-peak periods, or even peak hours, demand multipliers may therefore replicate demand variation more accurately if they are based on traffic volumes concurred in time intervals narrower than a day. This paper investigates six criteria or periods to derive demand multipliers: full-day, pre AM-peak, AM peak-period, midday, PM peak-period, and post PM-peak. The study explores how these periods affect the scale of demand multipliers and the travel time reliability assessment. It was found that the main statistics of demand multipliers, that is, the mean, range, and standard deviation, greatly differ across the different multiplying periods. If analyzing peak periods on oversaturated corridors, the adoption of daily-volume multipliers was found to significantly overestimate the mean travel time index and planning time index during both the AM and PM peak periods, the accuracy of the travel time reliability estimation was considerably influenced. The study concludes with major findings and recommendations for possible enhancements to the HCM travel time reliability procedure.

scholarly journals Relationship between large-scale ionospheric field-aligned currents and electron/ion precipitations: DMSP observations

2020 ◽  
Vol 72 (1) ◽  
Author(s):  
Chao Xiong ◽  
Claudia Stolle ◽  
Patrick Alken ◽  
Jan Rauberg
Keyword(s):  
Time Distribution ◽  
Large Scale ◽  
Particle Flux ◽  
Particle Energy ◽  
Lower Latitude ◽  
Particle Precipitation ◽  
Data Set ◽  
The Mean ◽  
Two Parameters ◽  
Meteorological Satellite

Abstract In this study, we have derived field-aligned currents (FACs) from magnetometers onboard the Defense Meteorological Satellite Project (DMSP) satellites. The magnetic latitude versus local time distribution of FACs from DMSP shows comparable dependences with previous findings on the intensity and orientation of interplanetary magnetic field (IMF) By and Bz components, which confirms the reliability of DMSP FAC data set. With simultaneous measurements of precipitating particles from DMSP, we further investigate the relation between large-scale FACs and precipitating particles. Our result shows that precipitation electron and ion fluxes both increase in magnitude and extend to lower latitude for enhanced southward IMF Bz, which is similar to the behavior of FACs. Under weak northward and southward Bz conditions, the locations of the R2 current maxima, at both dusk and dawn sides and in both hemispheres, are found to be close to the maxima of the particle energy fluxes; while for the same IMF conditions, R1 currents are displaced further to the respective particle flux peaks. Largest displacement (about 3.5°) is found between the downward R1 current and ion flux peak at the dawn side. Our results suggest that there exists systematic differences in locations of electron/ion precipitation and large-scale upward/downward FACs. As outlined by the statistical mean of these two parameters, the FAC peaks enclose the particle energy flux peaks in an auroral band at both dusk and dawn sides. Our comparisons also found that particle precipitation at dawn and dusk and in both hemispheres maximizes near the mean R2 current peaks. The particle precipitation flux maxima closer to the R1 current peaks are lower in magnitude. This is opposite to the known feature that R1 currents are on average stronger than R2 currents.

scholarly journals Pseudosparse neural coding in the visual system of primates

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Sidney R. Lehky ◽  
Keiji Tanaka ◽  
Anne B. Sereno
Keyword(s):  
Neural Coding ◽  
Macaque Monkey ◽  
Implicit Assumption ◽  
Data Set ◽  
Efficient Coding ◽  
Population Responses ◽  
Lateral Intraparietal Cortex ◽  
Neural Populations ◽  
Neurophysiological Data ◽  
The Mean

AbstractWhen measuring sparseness in neural populations as an indicator of efficient coding, an implicit assumption is that each stimulus activates a different random set of neurons. In other words, population responses to different stimuli are, on average, uncorrelated. Here we examine neurophysiological data from four lobes of macaque monkey cortex, including V1, V2, MT, anterior inferotemporal cortex, lateral intraparietal cortex, the frontal eye fields, and perirhinal cortex, to determine how correlated population responses are. We call the mean correlation the pseudosparseness index, because high pseudosparseness can mimic statistical properties of sparseness without being authentically sparse. In every data set we find high levels of pseudosparseness ranging from 0.59–0.98, substantially greater than the value of 0.00 for authentic sparseness. This was true for synthetic and natural stimuli, as well as for single-electrode and multielectrode data. A model indicates that a key variable producing high pseudosparseness is the standard deviation of spontaneous activity across the population. Consistently high values of pseudosparseness in the data demand reconsideration of the sparse coding literature as well as consideration of the degree to which authentic sparseness provides a useful framework for understanding neural coding in the cortex.

SURGICAL PROCESS RE-ENGINEERING: CARPAL TUNNEL DECOMPRESSION — A MODEL

Hand Surgery ◽  
2004 ◽  
Vol 09 (01) ◽  
pp. 19-27 ◽  
Author(s):  
J. A. Casaletto ◽  
V. Rajaratnam
Keyword(s):  
Carpal Tunnel ◽  
Carpal Tunnel Release ◽  
Procedure Time ◽  
Original Process ◽  
Depth Analysis ◽  
New Process ◽  
Common Operation ◽  
The Mean ◽  
Operative Findings ◽  
Made In

Surgical process re-engineering is a methodology where the entire surgical process is systematically analysed and re-designed. The process starts with mapping of the current process followed by in-depth analysis of the existing process. A new process is drafted with the aim of making the whole procedure more efficient. The new process is then discussed with all the staff involved in the operating room. Following implementation of the process, surgical process re-engineering should ideally be routinely carried out to continuously improve the procedure. We present an example of surgical process re-engineering which we carried out on the procedure of carpal tunnel release. We used carpal tunnel release as a model as it is a very common operation, with predictable intra-operative findings, and the patient is likely to benefit directly from procedure time reduction. A preliminary mapping of three procedures was done followed by a detailed timed mapping of five routine carpal tunnel decompression procedures. The mapped process was analysed in detail and a number of changes were made in the process. After implementing the new process, a further five procedures were mapped and timed again. In comparison to the original process, we achieved a reduction of 20% in the mean procedure time and a reduction of 42% in the number of steps from 66 to 37.

scholarly journals Numerical simulations of spreading of the Persian Gulf outflow into the Oman Sea

Ocean Science ◽  
2010 ◽  
Vol 6 (4) ◽  
pp. 887-900 ◽  
Author(s):  
M. Ezam ◽  
A. A. Bidokhti ◽  
A. H. Javid
Keyword(s):  
Persian Gulf ◽  
Bottom Topography ◽  
World Ocean ◽  
Monthly Precipitation ◽  
Boundary Current ◽  
Surface Salinity ◽  
Data Set ◽  
Open Boundaries ◽  
The Mean ◽  
The Persian Gulf

Abstract. A three dimensional numerical model namely POM (Princeton Ocean Model) and observational data are used to study the Persian Gulf outflow structure and its spreading pathways during 1992. In the model, the monthly wind speed data were taken from ICOADS (International Comprehensive Ocean-Atmosphere Data Set) and the monthly SST (sea surface temperatures) were taken from AVHRR (Advanced Very High Resolution Radiometer) with the addition of monthly net shortwave radiations from NCEP (National Center for Environmental Prediction). The mean monthly precipitation rates from NCEP data and the calculated evaporation rates are used to impose the surface salinity fluxes. At the open boundaries the temperature and salinity were prescribed from the mean monthly climatological values from WOA05 (World Ocean Atlas 2005). Also the four major components of the tide were prescribed at the open boundaries. The results show that the outflow mainly originates from two branches at different depths in the Persian Gulf. The permanent branch exists during the whole year deeper than 40 m along the Gulf axis and originates from the inner parts of the Persian Gulf. The other seasonal branch forms in the vicinity of the shallow southern coasts due to high evaporation rates during winter. Near the Strait of Hormuz the two branches join and form the main outflow source water. The results of simulations reveal that during the winter the outflow boundary current mainly detaches from the coast well before Ras Al Hamra Cape, however during summer the outflow seems to follow the coast even after this Cape. This is due to a higher density of the colder outflow that leads to more sinking near the coast in winter. Thus, the outflow moves to a deeper depth of about 500 m (for which some explanations are given) while the main part detaches and spreads at a depth of about 300 m. However in summer it all moves at a depth of about 200–250 m. During winter, the deeper, stronger and wider outflow is more affected by the steep topography, leading to separation from the coast. While during summer, the weaker and shallower outflow is less influenced by bottom topography and so continues along the boundary.

scholarly journals Neural Network Approach for Predicting Ship Speed and Fuel Consumption

2021 ◽  
Vol 9 (2) ◽  
pp. 119
Author(s):  
Lúcia Moreira ◽  
Roberto Vettor ◽  
Carlos Guedes Soares
Keyword(s):  
Neural Network ◽  
Fuel Consumption ◽  
Computing System ◽  
Fuel Oil ◽  
Network Computing ◽  
Peak Period ◽  
Neural Network Approach ◽  
Data Set ◽  
Navigation Data ◽  
Ship Speed

In this paper, simulations of a ship travelling on a given oceanic route were performed by a weather routing system to provide a large realistic navigation data set, which could represent a collection of data obtained on board a ship in operation. This data set was employed to train a neural network computing system in order to predict ship speed and fuel consumption. The model was trained using the Levenberg–Marquardt backpropagation scheme to establish the relation between the ship speed and the respective propulsion configuration for the existing sea conditions, i.e., the output torque of the main engine, the revolutions per minute of the propulsion shaft, the significant wave height, and the peak period of the waves, together with the relative angle of wave encounter. Additional results were obtained by also using the model to train the relationship between the same inputs used to determine the speed of the ship and the fuel consumption. A sensitivity analysis was performed to analyze the artificial neural network capability to forecast the ship speed and fuel oil consumption without information on the status of the engine (the revolutions per minute and torque) using as inputs only the information of the sea state. The results obtained with the neural network model show very good accuracy both in the prediction of the speed of the vessel and the fuel consumption.

scholarly journals EPID-22. CHARACTERIZATION OF RADIATION-INDUCED MENINGIOMAS IN A BRAIN TUMOR DATABASE

2020 ◽  
Vol 22 (Supplement_2) ◽  
pp. ii83-ii83
Author(s):  
Nilan Vaghjiani ◽  
Andrew Schwieder ◽  
Sravya Uppalapati ◽  
Zachary Kons ◽  
Elizabeth Kazarian ◽  
...  
Keyword(s):  
African American ◽  
Brain Tumor ◽  
Radiation Treatment ◽  
Latency Period ◽  
Data Set ◽  
Who Grade ◽  
Significant Difference ◽  
Radiation Induced ◽  
Grade Ii ◽  
The Mean

Abstract PURPOSE Radiation-induced meningiomas (RIMs) are associated with previous exposure to therapeutic irradiation. RIMs are rare and have not been well characterized relative to spontaneous meningiomas (SMs). METHODS 1003 patients with proven or presumed meningiomas were identified from the VCU brain tumor database. Chart review classified RIM patients and their characteristics. RESULTS Of the 1003 total patients, 76.47% were female with a mean ± SD age of 67.55 ± 15.50 years. 15 RIM patients were identified (66.67% female), with a mean ± SD age of 52.67 ± 15.46 years, 5 were African American and 10 were Caucasian. The incidence of RIMs was 1.49% in our data set. The mean age at diagnosis was 43.27 ± 15.06 years. The mean latency was 356.27 ± 116.96 months. The mean initiating dose was 44.28 ± 14.68 Gy. There was a significant difference between mean latency period and ethnicity, 258.3 months for African American population, and 405.2 months for Caucasian population (p = 0.003). There was a significant difference between the mean number of lesions in females (2.8) versus males (1.2; p = 0.046). Of the RIMs with characterized histology, 6 (55%) were WHO grade II and 5 (45%) were WHO grade I, demonstrating a prevalence of grade II tumors approximately double that found with SMs. RIMs were treated with combinations of observation, surgery, radiation, and medical therapy. Of the 8 patients treated with radiation, 4 demonstrated response. 8 of the 15 patients (53%) demonstrated recurrence/progression despite treatment. CONCLUSION RIMs are important because of the associated higher grade histology, gender, and ethnic incidences, and increased recurrence/progression compared to SMs. Despite the presumed contributory role of prior radiation, RIMs demonstrate a significant rate of responsiveness to radiation treatment.

Analyzing Travel Time Reliability from Sparse Probe Vehicle Data: A Case Study on the Effects of Spatial and Temporal Aggregation

2021 ◽  
pp. 036119812110315
Author(s):  
Markus Steinmaßl ◽  
Stefan Kranzinger ◽  
Karl Rehrl
Keyword(s):  
Travel Time ◽  
Time Of Day ◽  
Temporal Aggregation ◽  
Travel Time Reliability ◽  
Probe Vehicle ◽  
Vehicle Data ◽  
Depth Analysis ◽  
Data Source ◽  
Travel Time Index

Travel time reliability (TTR) indices have gained considerable attention for evaluating the quality of traffic infrastructure. Whereas TTR measures have been widely explored using data from stationary sensors with high penetration rates, there is a lack of research on calculating TTR from mobile sensors such as probe vehicle data (PVD) which is characterized by low penetration rates. PVD is a relevant data source for analyzing non-highway routes, as they are often not sufficiently covered by stationary sensors. The paper presents a methodology for analyzing TTR on (sub-)urban and rural routes with sparse PVD as the only data source that could be used by road authorities or traffic planners. Especially in the case of sparse data, spatial and temporal aggregations could have great impact, which are investigated on two levels: first, the width of time of day (TOD) intervals and second, the length of road segments. The spatial and temporal aggregation effects on travel time index (TTI) as prominent TTR measure are analyzed within an exemplary case study including three different routes. TTI patterns are calculated from data of one year grouped by different days-of-week (DOW) groups and the TOD. The case study shows that using well-chosen temporal and spatial aggregations, even with sparse PVD, an in-depth analysis of traffic patterns is possible.

A Novel Nonsurgical Technique for Correcting Congenital Auricular Anomalies

2021 ◽  
Author(s):  
Shay I. Duvdevani ◽  
Hadas Knoller ◽  
Noa Rozendorn ◽  
Eran E. Alon ◽  
Ory Madgar
Keyword(s):  
Treatment Initiation ◽  
Neonatal Period ◽  
Cost Effective ◽  
Normal Appearance ◽  
Time Saving ◽  
Effective Time ◽  
Custom Made ◽  
The Mean ◽  
Ear Anomalies ◽  
Surgical Corrections

AbstractCongenital ear anomalies are associated with psychological morbidity. Ear deformities can usually be corrected by nonsurgical techniques such as splinting or molding in the neonatal period, initiated before 6 weeks. Without early corrections, many will require otoplasty during childhood. We introduce a novel silicone-based custom mold technique for congenital ear anomalies. The highly malleable silicone was pushed into every part of the auricle, enabling the auricle to remain in the desired shape, with new molds made weekly. Of 31 newborns (18 males, 13 females), 54 ears were treated. Average age at treatment initiation was 26.8 days. The mean treatment duration was 43.2 days, with a median of 28 days. Normal appearance and parent's satisfaction were achieved in 30 patients with 49 deformed ears and also in four newborns older than 6 weeks. Three concha type microtia in two patients achieved great improvements and parents' satisfaction. No complications were reported. Marked aesthetic improvements and normal appearance were achieved for all deformed auricles treated, and improvements in the concha type microtia will partially alleviate future surgical corrections. The results are not inferior to other techniques. The advantages are as follows: cost-effective, time-saving, simple to master, no need for hair shaving, and easy use for parents. Patients older than 6 weeks of age achieved normal auricle appearance, enabling the correction in older newborns. Custom made silicone auricle molding offers a simple nonsurgical technique for correcting congenital ear anomalies, alleviating the need for future surgical corrections.

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