scholarly journals Modeling and Predicting Stochastic Merging Behaviors at Freeway On-Ramp Bottlenecks

2018 ◽  
Vol 2018 ◽  
pp. 1-15 ◽  
Author(s):  
Jian Sun ◽  
Kang Zuo ◽  
Shun Jiang ◽  
Zuduo Zheng
Keyword(s):  
Los Angeles ◽  
Great Influence ◽  
Data Sets ◽  
Gap Acceptance ◽  
Trajectory Data ◽  
Logistic Regression Models ◽  
Critical Gap ◽  
Merging Behavior ◽  
The Impact ◽  
Gap Acceptance Theory

Merging behavior is inevitable at on-ramp bottlenecks and is a significant factor in triggering traffic breakdown. In modeling merging behaviors, the gap acceptance theory is generally used. Gap acceptance theory holds that when a gap is larger than the critical gap, the vehicle will merge into the mainline. In this study, however, analyses not only focus on the accepted gaps, but also take the rejected gaps into account, and the impact on merging behavior with multi-rejected (more than once rejecting behavior) gaps was investigated; it shows that the multi-rejected gaps have a great influence on the estimation of critical gap and merging prediction. Two empirical trajectory data sets were collected and analyzed: one at Yan’an Expressway in Shanghai, China, and the other at Highway 101 in Los Angeles, USA. The study made three main contributions. First, it gives the quantitative measurement of the rejected gap which is also a detailed description of non-merging event and investigated the characteristics of the multi-rejected gaps; second, taking the multi-rejected gaps into consideration, it further expanded the concept of the “critical gap” which can be a statistic one and the distribution function of merging probability with respect to such gaps was analyzed by means of survival analysis. This way could make the full use of multi-rejected gaps and accepted gaps and reduce the sample bias, thus estimating the critical gap accurately; finally, considering multi-rejected gaps, it created logistic regression models to predict merging behavior. These models were tested using field data, and satisfactory performances were obtained.

scholarly journals Critical Gaps at Unsignalized Intersections with Bending Right-of-Way

2018 ◽  
Vol 20 (4) ◽  
pp. 69-75
Author(s):  
Andrea Kocianova ◽  
Eva Pitlova
Keyword(s):  
Calculation Procedure ◽  
Gap Acceptance ◽  
Driver Behaviour ◽  
Critical Gap ◽  
Right Of Way ◽  
Unsignalized Intersections ◽  
Capacity Calculation ◽  
Rank 2 ◽  
Gap Acceptance Theory ◽  
Traffic Rules

The capacity calculation procedure for unsignalized intersections is based on the gap-acceptance theory in most of existing capacity regulations and it relies on one of the important parameters - critical gap. However, the capacity calculation procedure and values of critical gaps according to these regulations are valid only for intersections with standard right-of-way (major street leading straight). Nevertheless, in Slovakia, intersections with bending right-of-way (major street not leading straight, but bending) can be encountered. The specific mode of right-of-way results in different priority ranks of traffic movements (set by traffic rules of driving), more complicated traffic situation and therefore, different driver behaviour characteristics. To examine the gap acceptance behaviour of drivers under these specific conditions, an unsignalized four-leg intersection with bending right-of-way located in an urban area of Zilina, Slovakia, was selected. Three different methods (Raff, Wu, and MLM Troutbeck) were used for critical gap estimation from the field data. In the article, results of critical gaps for three through movements of different priority rank (major-street through movement of Rank 2 and minor-street through movements of Rank 3 and 4) are presented. The results show, that the values of critical gaps differ depending on the method by about 3-5 % only, which is not significant. Troutbeck ´s MLM method gives the highest values. The priority rank of movement has the greatest impact on the result. The values of critical gap for major-street through movement of Rank 2 are the smallest; they are approximately 1.3-2.1 s smaller than the values for minor-street through movements of Rank 3 or 4. The highest values of critical gap have been estimated for minor-street through movement of Rank 4 and they are higher compared to the current Slovak regulations TP 102 values for the same priority rank.

scholarly journals Capacity Prediction Model Based on Limited Priority Gap-Acceptance Theory at Multilane Roundabouts

2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
Zhaowei Qu ◽  
Yuzhou Duan ◽  
Xianmin Song ◽  
Hongyu Hu ◽  
Huanfeng Liu ◽  
...  
Keyword(s):  
Likelihood Estimation ◽  
Gap Acceptance ◽  
Modified Model ◽  
Field Surveys ◽  
Critical Gap ◽  
Proposed Model ◽  
Acceptance Model ◽  
The Relationship ◽  
Gap Acceptance Theory ◽  
Important Design

Capacity is an important design parameter for roundabouts, and it is the premise of computing their delay and queue. Roundabout capacity has been studied for decades, and empirical regression model and gap-acceptance model are the two main methods to predict it. Based on gap-acceptance theory, by considering the effect of limited priority, especially the relationship between limited priority factor and critical gap, a modified model was built to predict the roundabout capacity. We then compare the results between Raff’s method and maximum likelihood estimation (MLE) method, and the MLE method was used to predict the critical gaps. Finally, the predicted capacities from different models were compared, with the observed capacity by field surveys, which verifies the performance of the proposed model.

Capacity Estimation on Turboroundabouts with Gap Acceptance and Flow Level Methods

2015 ◽  
Vol 2517 (1) ◽  
pp. 71-79 ◽  
Author(s):  
Lambertus G. H. Fortuijn ◽  
Serge P. Hoogendoorn
Keyword(s):  
Linear Model ◽  
Traffic Flow ◽  
Linear Models ◽  
Data Sources ◽  
Gap Acceptance ◽  
Capacity Estimation ◽  
Flow Measurements ◽  
Critical Gap ◽  
Behavioral Parameters ◽  
Gap Acceptance Theory

In the literature, linear models and exponential models based on gap acceptance theory are distinguished. Parameters for the linear models can be estimated only at the level of traffic flow, whereas the gap acceptance theory assumes that behavioral parameters (critical gap, follow-on time, and minimum headway) can be estimated at the vehicle level, and then capacity can be determined. However, in the latter method, measurements must also be made under saturated conditions because of so-called pseudoconflict (caused by vehicles leaving the roundabout in the opposite leg direction). An analysis of data sources (vehicle level and traffic flow level) indicates that the parameters estimated at the vehicle level correspond with those estimated at the level of traffic flow for single-lane roundabouts, but not for more complex situations. Despite this deficiency, better results can be gained with a model based on the present gap acceptance theory than with a linear model, provided that the parameters are adjusted to consider traffic flow measurements under saturated conditions. Additional research will be necessary to determine which underlying assumptions of the gap acceptance models cause these deficiencies. In Germany, capacity is higher in turboroundabouts than in compact two-lane roundabouts because of better use of the inner lane in the turboroundabout.

The Doctor Faustus Dossier

2018 ◽  
Author(s):  
Adrian Daub
Keyword(s):  
Twentieth Century ◽  
Los Angeles ◽  
Primary Source ◽  
Music And Literature ◽  
Twentieth Century Music ◽  
Private And Public ◽  
Doctor Faustus ◽  
Public Lives ◽  
Nazi Era ◽  
The Impact

Arnold Schoenberg and Thomas Mann, two towering figures of twentieth-century music and literature, both found refuge in the German-exile community in Los Angeles during the Nazi era. This complete edition of their correspondence provides a glimpse inside their private and public lives and culminates in the famous dispute over Mann's novel Doctor Faustus. In the thick of the controversy was Theodor Adorno, then a budding philosopher, whose contribution to the Faustus affair would make him an enemy of both families. Gathered here for the first time in English, the letters are complemented by diary entries, related articles, and other primary source materials, as well as an introduction that contextualizes the impact that these two great artists had on twentieth-century thought and culture.

Role of Brand experience in Fashion brands

2019 ◽  
Vol 118 (1) ◽  
pp. 57-64
Author(s):  
G. Aiswarya ◽  
Dr. Jayasree Krishnan
Keyword(s):  
Factor Analysis ◽  
Purchase Intention ◽  
Great Influence ◽  
Brand Experience ◽  
Brand Preference ◽  
Mediating Role ◽  
Confirmatory Factor ◽  
Selling Strategies ◽  
The Impact

Traditionally the products were pushed into the hands of customers by production and selling strategies; then the marketing strategy evolved which gained momentum by understanding the customer needs and developing products satisfying those needs. This strategy is most prevalent and what should be done to stand up in this most competitive scenario? The answer to this key question is to create an experience. The customers now also seek good experiences than other benefits. Brand experience has gained more attention, especially fashion brands. Previous studies demonstrate the role of the brand experience in brand equity and other consumer behavior constructs. But very little is known about the impact of brand experiences on fashion brands. The aim of this study is to develop a model which makes our understanding better about the role of Brand preference and Brand experience and its influence on purchase intention of the brand. An initial exploratory study is conducted using a focus group to generate items for the study. The items, thus generated are prepared in the form of a questionnaire and samples were collected.  Exploratory factor analysis is conducted and the reliability of the constructs is determined. These constructs are loaded onto AMOS to perform Confirmatory factor analysis. The results confirmed the scales used. We also noticed that Brand preference has a great influence on the Brand experience. Thereby the finding supports the role of the brand experience which tends to have a mediating role in influencing the purchase intention.

The impact of SPY angiography on intraoperative decision making and outcomes for post-mastectomy reconstruction

2019 ◽  
pp. 1-5
Keyword(s):  
Decision Making ◽  
Logistic Regression ◽  
Skin Necrosis ◽  
Regression Models ◽  
Multivariable Analysis ◽  
P Value ◽  
Flap Necrosis ◽  
Single Institution ◽  
Logistic Regression Models ◽  
The Impact

Objective: While the use of intraoperative laser angiography (SPY) is increasing in mastectomy patients, its impact in the operating room to change the type of reconstruction performed has not been well described. The purpose of this study is to investigate whether SPY angiography influences post-mastectomy reconstruction decisions and outcomes. Methods and materials: A retrospective analysis of mastectomy patients with reconstruction at a single institution was performed from 2015-2017.All patients underwent intraoperative SPY after mastectomy but prior to reconstruction. SPY results were defined as ‘good’, ‘questionable’, ‘bad’, or ‘had skin excised’. Complications within 60 days of surgery were compared between those whose SPY results did not change the type of reconstruction done versus those who did. Preoperative and intraoperative variables were entered into multivariable logistic regression models if significant at the univariate level. A p-value <0.05 was considered significant. Results: 267 mastectomies were identified, 42 underwent a change in the type of planned reconstruction due to intraoperative SPY results. Of the 42 breasts that underwent a change in reconstruction, 6 had a ‘good’ SPY result, 10 ‘questionable’, 25 ‘bad’, and 2 ‘had areas excised’ (p<0.01). After multivariable analysis, predictors of skin necrosis included patients with ‘questionable’ SPY results (p<0.01, OR: 8.1, 95%CI: 2.06 – 32.2) and smokers (p<0.01, OR:5.7, 95%CI: 1.5 – 21.2). Predictors of any complication included a change in reconstruction (p<0.05, OR:4.5, 95%CI: 1.4-14.9) and ‘questionable’ SPY result (p<0.01, OR: 4.4, 95%CI: 1.6-14.9). Conclusion: SPY angiography results strongly influence intraoperative surgical decisions regarding the type of reconstruction performed. Patients most at risk for flap necrosis and complication post-mastectomy are those with questionable SPY results.

scholarly journals Investigating the impact of pre-processing techniques and pre-trained word embeddings in detecting Arabic health information on social media

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Yahya Albalawi ◽  
Jim Buckley ◽  
Nikola S. Nikolov
Keyword(s):  
Social Media ◽  
Deep Learning ◽  
Comprehensive Evaluation ◽  
Classification Problem ◽  
Data Sets ◽  
Word Embeddings ◽  
Data Set ◽  
Lower Accuracy ◽  
Health Related ◽  
The Impact

AbstractThis paper presents a comprehensive evaluation of data pre-processing and word embedding techniques in the context of Arabic document classification in the domain of health-related communication on social media. We evaluate 26 text pre-processings applied to Arabic tweets within the process of training a classifier to identify health-related tweets. For this task we use the (traditional) machine learning classifiers KNN, SVM, Multinomial NB and Logistic Regression. Furthermore, we report experimental results with the deep learning architectures BLSTM and CNN for the same text classification problem. Since word embeddings are more typically used as the input layer in deep networks, in the deep learning experiments we evaluate several state-of-the-art pre-trained word embeddings with the same text pre-processing applied. To achieve these goals, we use two data sets: one for both training and testing, and another for testing the generality of our models only. Our results point to the conclusion that only four out of the 26 pre-processings improve the classification accuracy significantly. For the first data set of Arabic tweets, we found that Mazajak CBOW pre-trained word embeddings as the input to a BLSTM deep network led to the most accurate classifier with F1 score of 89.7%. For the second data set, Mazajak Skip-Gram pre-trained word embeddings as the input to BLSTM led to the most accurate model with F1 score of 75.2% and accuracy of 90.7% compared to F1 score of 90.8% achieved by Mazajak CBOW for the same architecture but with lower accuracy of 70.89%. Our results also show that the performance of the best of the traditional classifier we trained is comparable to the deep learning methods on the first dataset, but significantly worse on the second dataset.

Outcomes of Passable and Non-passable Strictures in Clinical Trials of Crohn’s Disease: A Post-hoc Analysis

2021 ◽  
Author(s):  
Neeraj Narula ◽  
Emily C L Wong ◽  
Parambir S Dulai ◽  
John K Marshall ◽  
Jean-Frederic Colombel ◽  
...  
Keyword(s):  
Crohn’S Disease ◽  
Crohn's Disease ◽  
Activity Index ◽  
Disease Activity Index ◽  
Symptom Improvement ◽  
Logistic Regression Models ◽  
Post Hoc Analysis ◽  
Endoscopic Remission ◽  
Post Hoc ◽  
The Impact

Abstract Background and Aims There is paucity of evidence on the reversibility of Crohn’s disease [CD]-related strictures treated with therapies. We aimed to describe the clinical and endoscopic outcomes of CD patients with non-passable strictures. Methods This was a post-hoc analysis of three large CD clinical trial programmes examining outcomes with infliximab, ustekinumab, and azathioprine, which included data on 576 patients including 105 with non-passable strictures and 45 with passable strictures, as measured using the Simple Endoscopic Score for Crohn’s Disease [SES-CD]. The impact of non-passable strictures on achieving clinical remission [CR] and endoscopic remission [ER] was assessed using multivariate logistic regression models. CR was defined as a Crohn’s Disease Activity Index [CDAI] &lt;150, clinical response as a CDAI reduction of ≥100 points, and ER as SES-CD score &lt;3. Results After 1 year of treatment, patients with non-passable strictures demonstrated the ability to achieve passable or no strictures in 62.5% of cases, with 52.4% and 37.5% attaining CR and ER, respectively. However, patients with non-passable strictures at baseline were less likely to demonstrate symptom improvement compared with those with passable or no strictures, with reduced odds of 1-year CR (adjusted odds ratio [aOR] 0.17, 95% CI 0.03–0.99, p = 0.048). No significant differences were observed between patients with non-passable strictures at baseline and those with passable or no strictures in rates of ER [aOR 0.82, 95% CI 0.23–2.85, p = 0.751] at 1 year. Conclusions Patients with non-passable strictures can achieve symptomatic and endoscopic remission when receiving therapies used to treat CD, although they are less likely to obtain CR compared with patients without non-passable strictures. These findings support the importance of balancing the presence of non-passable strictures in trial arms.

516 Impacts of Chronic Nausea and Vomiting on Daytime Sleepiness and Fatigue

SLEEP ◽  
2021 ◽  
Vol 44 (Supplement_2) ◽  
pp. A203-A203
Author(s):  
Maurice Ohayon ◽  
Y J Chen ◽  
Marie-Lise Cote
Keyword(s):  
Longitudinal Study ◽  
Daytime Sleepiness ◽  
Nausea And Vomiting ◽  
Prospective Longitudinal Study ◽  
Logistic Regression Models ◽  
Related Quality ◽  
Health Related ◽  
Chronic Nausea ◽  
Prospective Longitudinal ◽  
The Impact

Abstract Introduction Chronic nausea and vomiting (CNV), common symptoms in patients with GI disorders like gastroparesis, can be a debilitating health problem with considerable impact on patients’ health-related quality of life during daytime. Yet, little is known about how CNV may impact on sleepiness and fatigue during the daytime. Our aim was to examine the impact of CNV on daytime sleepiness and fatigue based on the data from a longitudinal study. Methods Prospective longitudinal study with two waves: 12,218 subjects interviewed by phone during wave 1 (W1); 10,931 during wave 2 (W2) three years later. The sample was representative of the US general population. Analyses included subjects participating to both waves (N=10,931). CNV was defined as episodes of nausea and vomiting occurring at least twice a month for at least 1 month (outside pregnancy). Logistic regression models were employed to determine whether CNV is a predictive variable for excessive sleepiness or fatigue. Results Out of all W1 participants, 9.8% (95% CI: 9.2%-10.4%) reported nausea only while 3% (95% CI: 2.7%-3.3%) reported CNV. In W2, 7.7% (95% CI: 7.2%-8.2%) reported nausea only and 2.5% (95% CI: 2.2%-2.8%) reported having CNV. Of the subjects who participated in both W1 and W2, 25.7% of them reported CNV in W1. CNV subjects reported more frequently excessive daytime sleepiness (53.5% vs. 25.9%) and being moderately or severely fatigued (38.6% vs, 5.4%) compared with the participants without nausea or vomiting. After controlling for age, sex, BMI, health status, alcohol intake, sleep disorders and psychiatric disorders that might impact on daytime sleepiness or fatigue, it was found that subjects with CNV at both W1 and W2 had a significantly higher relative risk of reporting daytime sleepiness (RR: 2.7 (95% CI:1.9–3.9) p&lt;0.0001) and fatigue (RR: 4.9 (95% CI:3.2–7.5) p&lt;0.0001) at W2, compared with the participants without nausea or vomiting. Conclusion Many factors are likely to influence daytime sleepiness. CNV appears to be an important contributor even after controlling for several factors that can explain the sleepiness. This underlines the extent to which alertness could be disturbed and impacted by chronicity of nausea/vomiting symptoms. Support (if any) This analysis study was funded by Takeda Pharmaceutical Company

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