Search

Objective: Delay in the diagnosis of tuberculosis (TB) is a significant problem at both individual and community levels. Delayed diagnosis of TB contributes to more severe disease manifestations, higher risk of death, and higher disease transmission in the community. We conducted this study to assess the extent and associated reasons for delay in diagnosis of pulmonary TB. Methods: This study was conducted in the Department of TB and Respiratory Diseases, J. N. Medical College, Aligarh, from June 2020 to May 2022. A total of 2053 new pulmonary TB patients, who first consulted any private healthcare provider (HCP) for treatment, were enrolled in the study. The required information was collected by interview technique using a predesigned questionnaire. Results: A total of 2053 patients were enrolled in the study. There was a significant delay of more than 2 weeks in the diagnosis of pulmonary TB after the onset of symptoms in 94% of patients. The extent of delay ranged from 8 days to 240 days with a mean of 36.33 days. The delay in visiting the HCPs by the patient was not significant. Only 5.85% of patients had a significant delay of more than 2 weeks in seeking any health care after the appearance of symptoms. A delay by HCP contributed to a greater portion of the total delay, with a mean of 31.77 days. The main reason for the delay by HCPs was not investigating TB. The hospital delay was not significant. The mean hospital delay was 5.82 days. Conclusion: The delay in the diagnosis of TB in India is very high. A delay by HCPs contributes to a greater portion of the total delay. Information, Education and Communication (IEC) activities will play an important role in reducing the delay. All HCPs should be actively involved in subjecting the suspects to TB diagnosis at the earliest possible as per National Tuberculosis Elimination Programme (NTEP) guidelines.

Objective: Delay in the diagnosis of tuberculosis (TB) is a significant problem at both individual and community levels. Delayed diagnosis of TB contributes to more severe disease manifestations, higher risk of death, and higher disease transmission in the community. We conducted this study to assess the extent and associated reasons for delay in diagnosis of pulmonary TB. Methods: This study was conducted in the Department of TB and Respiratory Diseases, J. N. Medical College, Aligarh, from June 2020 to May 2022. A total of 2053 new pulmonary TB patients, who first consulted any private healthcare provider (HCP) for treatment, were enrolled in the study. The required information was collected by interview technique using a predesigned questionnaire. Results: A total of 2053 patients were enrolled in the study. There was a significant delay of more than 2 weeks in the diagnosis of pulmonary TB after the onset of symptoms in 94% of patients. The extent of delay ranged from 8 days to 240 days with a mean of 36.33 days. The delay in visiting the HCPs by the patient was not significant. Only 5.85% of patients had a significant delay of more than 2 weeks in seeking any health care after the appearance of symptoms. A delay by HCP contributed to a greater portion of the total delay, with a mean of 31.77 days. The main reason for the delay by HCPs was not investigating TB. The hospital delay was not significant. The mean hospital delay was 5.82 days. Conclusion: The delay in the diagnosis of TB in India is very high. A delay by HCPs contributes to a greater portion of the total delay. Information, Education and Communication (IEC) activities will play an important role in reducing the delay. All HCPs should be actively involved in subjecting the suspects to TB diagnosis at the earliest possible as per National Tuberculosis Elimination Programme (NTEP) guidelines. [ABSTRACT FROM AUTHOR]

Introduction: The incidence of cancer is increasing throughout the world. However, early detection of cancers is associated with a favourable outcome. Stomach cancer is one of the most common cancers of gastrointestinal tract. Majority patients visit physicians in developed stages. Objective: To evaluate the reporting pattern of stomach cancer patients living in Kashmir valley in order to determine the median time of delay from the beginning of symptoms to diagnosis. Method: Total 116 proven stomach cancer patients were evaluated for the pattern of presentation at endoscopy laboratory of Super Speciality Hospital, Shireen Bagh Kashmir from April 2019 to September 2020.Results: In this study, the mean age (SD) of participants was 60.22 ± (11.90) years. Majority of the participants (69.8%) were males. Cases were predominantly from the rural area (58%).Only 15.5 % of the cases were diagnosed within one month of their symptoms while as 3.4% of the cases had a total delay of more than 12 months. The study found a considerable total delay in the diagnosis of stomach cancer. The mean of the patient delay was 45.6 days. The median total delay was 20 weeks. Conclusion: Since stomach cancer has high mortality and morbidity rates associated, creating awareness among the population and training of physicians regarding timely referral of patients seems important.

The main factor in the airline transport service being the reason for the choice is the place and time benefit it provides. Delays are negative situations that disrupt the time utility, reduce airlines' profits, cause congestion trouble and disrupt tariff plans. The first part of the study consists of information about delays and fundamental issues related to delays. In the second part, it has been tried to summarize the studies on the slot, which is directly related to the delays. In the last part, two airlines that adopted different business models, full-service carrier and low-cost carrier, were compared based on delay reasons. The study aims to determine the causes of delay and their predictive roles comparatively. We have used the multiple hierarchical regression model for this purpose. American Airlines and Southwest Airlines were selected as full-service carrier and low-cost carrier, respectively. We have determined that even though Southwest Airlines is a low-cost carrier, and more punctual than American Airlines, delays stemming from the carrier play a greater role in overall delays than American Airlines.

Copyright of Journal of Research of the University of Quindio / Revista de Investigaciones Universidad del Quindio is the property of Journal of Research of the University of Quindio and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Transit Signal Priority (TSP) has been proposed and implemented to reduce transit travel time, provide better schedule adherence, and improve transit efficiency. However, concerns have been raised about causing delays to cross street and left-turn movements. The cost-effective implementation of TSP requires methods to support the decisions associated with the implementation. The objective of this research was to examine the existing TSP guidance and propose enhanced planning-level guidelines for TSP deployment that can be applied to identify intersections where implementing TSP is beneficial. The proposed guidelines take consideration of bus delay, bus frequency, geometric and traffic feasibility, as well as the impacts on other movements. The effectiveness of the proposed guidelines was evaluated in comparison with existing guidelines using a microscopic simulation approach. The simulation results showed that the proposed TSP guidelines produce a better-balanced solution for minimizing both main street bus travel times and delays for other affected movements. The proposed guidelines also help to cut the TSP implementation costs by reducing the number of intersections identified for TSP implementation. [ABSTRACT FROM AUTHOR]

Abstract Background Early diagnosis and treatment of pulmonary tuberculosis (PTB) is essential for an effective control of the tuberculosis (TB) epidemic. Delayed diagnosis and treatment of TB increases the chance of complications and mortality for the patients, and enhances TB transmission in the population. Therefore, the aim of this study was to characterize patient, healthcare and total delay in diagnosing PTB and assess the effect of clinical and sociodemographic factors on the time until first contact with healthcare or reaching a PTB diagnosis. Methods Retrospective cohort study that included active PTB patients notified in the National Tuberculosis Surveillance System (SVIG-TB), between 2008 and 2017. Descriptive statistics, Kaplan-Meier estimates, logrank test and Cox proportional hazards model were used to characterize patient, healthcare and total delay and estimate the effect of clinical and sociodemographic variables on these delays. Significance level was set at 0.05. Results Median patient, healthcare and total delays was 37 days (Interquartile range (IQR): 19–71), 8 days (IQR: 1–32) and 62 days (IQR: 38–102), respectively. The median patient delay showed a constant increase, from 33 days in 2008 to 44 days in 2017. The median total delay presented a similar trend, increasing from 59 days in 2008 to 70 days in 2017. Healthcare delay remained constant during the study period. More than half of the PTB cases (82.9%) had a delay > 1 month between symptom onset and diagnosis. In the final Cox model, alcohol abuse, unemployment and being from a high TB incidence country were factors significantly associated with longer patient delay, while being female, having more than 45 years, oncologic and respiratory diseases were associated with longer healthcare delay. Being female, having more than 45 years and being from a high TB incidence country were associated with longer total delay. Conclusions Patient delay and total delay have increased in recent years. Older patients, patients with alcohol problems, other comorbidities, unemployed or from countries with high TB incidence would benefit from the development of specific public health strategies that could help reduce the delay in TB diagnosis observed in our study. This study emphasizes the need to promote awareness of TB in the general population and among the healthcare community, especially at ambulatory care level, in order to reduce the gap between beginning of symptoms and TB diagnosis.

Abstract Background Thirty countries with the highest tuberculosis (TB) burden bear 87% of the world’s TB cases. Delayed diagnosis and treatment are detrimental to TB prognosis and sustain TB transmission in the community, making TB elimination a great challenge, especially in these countries. Our objective was to elucidate the duration and determinants of delayed diagnosis and treatment of pulmonary TB in high TB-burden countries. Methods We conducted a systematic review and meta-analysis of quantitative and qualitative studies by searching four databases for literature published between 2008 and 2018 following PRISMA guidelines. We performed a narrative synthesis of the covariates significantly associated with patient, health system, treatment, and total delays. The pooled median duration of delay and effect sizes of covariates were estimated using random-effects meta-analyses. We identified key qualitative themes using thematic analysis. Results This review included 124 articles from 14 low- and lower-middle-income countries (LIC and LMIC) and five upper-middle-income countries (UMIC). The pooled median duration of delays (in days) were—patient delay (LIC/LMIC: 28 (95% CI 20–30); UMIC: 10 (95% CI 10–20), health system delay (LIC/LMIC: 14 (95% CI 2–28); UMIC: 4 (95% CI 2–4), and treatment delay (LIC/LMIC: 14 (95% CI 3–84); UMIC: 0 (95% CI 0–1). There was consistent evidence that being female and rural residence was associated with longer patient delay. Patient delay was also associated with other individual, interpersonal, and community risk factors such as poor TB knowledge, long chains of care-seeking through private/multiple providers, perceived stigma, financial insecurities, and poor access to healthcare. Organizational and policy factors mediated health system and treatment delays. These factors included the lack of resources and complex administrative procedures and systems at the health facilities. We identified data gaps in 11 high-burden countries. Conclusions This review presented the duration of delays and detailed the determinants of delayed TB diagnosis and treatment in high-burden countries. The gaps identified could be addressed through tailored approaches, education, and at a higher level, through health system strengthening and provision of universal health coverage to reduce delays and improve access to TB diagnosis and care. PROSPERO registration: CRD42018107237.

Objectives: Delay in diagnosis and treatment, called total delay, could probably result in lower survival rates in breast cancer patients. This study aimed to investigate the factors associated with the comprehensive delay behaviors and to evaluate its effect on outcomes in patients with breast cancer in Dalian, a northeast city of China. Methods: A retrospective chart review was conducted using a cancer registry dataset including 298 patients. The Kaplan–Meier survival analysis was used to identify the threshold of total delay, dividing the patients into a group with significant uncertainty and a group without substantial delay. The factors associated with the significant total delay were investigated from the potential candidates, like income level and marital status, by using the chi-squared test. The difference of the clinicopathologic characteristics between the patients grouped by the significant total delay, like tumor size and lymph node metastasis, was also investigated to find out the effect of the total delay. Results: A total of 238 charts were used for analysis. The mean age was 57.3. The median of total delays was 3.75 months. Thirty days was identified as a threshold, more than which the total delay can lead to worse survival. Patients' marital status (p = 0.010), income levels (p = 0.003), smoking status (p = 0.031), initial visiting hospital level (p = 0.005), self-health care (p = 0.001), and self-concern about initial symptom (p ≈ 0.000) were identified as the independent predictors of the total delay. Metastasis (p ≈ 0.000) was identified as the significant result relating to the significant total delay. Conclusions: A total delay of more than 30 days predicts worse survival in breast cancer patients in Dalian. Several factors, like patients' marital status and income levels, can be considered to be relevant to the significant total delay. We recommend that these factors be used to predict the potential patients with the significant total delay in the clinical practice. [ABSTRACT FROM AUTHOR]

Fentabil Getnet,1,2 Meaza Demissie,3 Alemayehu Worku,3,4 Tesfaye Gobena,2 Rea Tschopp,5– 7 Berhanu Seyoum5 1College of Medicine and Health Sciences, Jigjiga University, Jigjiga, Ethiopia; 2School of Public Health, Haramaya University, Harar, Ethiopia; 3Addis Continental Institute of Public Health, Addis Ababa, Ethiopia; 4School of Public Health, Addis Ababa University, Addis Ababa, Ethiopia; 5Armauer Hansen Research Institute, Addis Ababa, Ethiopia; 6Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Basel, Switzerland; 7University of Basel, Basel, SwitzerlandCorrespondence: Fentabil GetnetJigjiga University, P. O. Box 1020, Jigjiga, EthiopiaTel +251 913 289 380Email b.infen4ever@gmail.comPurpose: This study aimed to assess the extent of patient, health system and total delays in diagnosis and treatment of pulmonary tuberculosis (TB) in Somali pastoralist setting, Ethiopia.Patients and Methods: A cross-sectional study among 444 confirmed new pulmonary TB patients aged ≥ 15 years in 5 TB care units was conducted between December 2017 and October 2018. Data were collected using a structured questionnaire and record review. We measured delays from symptom onset to provider visit, provider visit to diagnosis and diagnosis to treatment initiation. Delays were summarized using median days. Mann–Whitney and Kruskal–Wallis tests were used to compare delays between categories of explanatory variables. The Log-binomial regression model was used to reveal factors associated with health system delay ≥ 15 days, presented in adjusted prevalence ratio (APR) with 95% confidence interval (CI).Results: The median age of patients was 30 years, ranged from 15 to 82. The majority (62.4%) were male, and nearly half (46.4%) were pastoralists. The median patient, health system and total delays were 30 (19– 48.5), 14 (4.5– 29.5) and 50 (35– 73.5) days, respectively. The median patient delay (35.5 days) and total delay (58.5 days) among pastoralists were substantially higher than the equivalent delays among non-pastoralists [p< 0.001]. Of all, 3.8% of patients (16 of 18 were pastoralists) delayed longer than 6 months without initiating treatment. Factors associated with health system delay ≥ 15 days were mild symptoms [APR (95% CI) = 1.4 (1.1– 1.7)], smear-negativity [APR (95% CI) = 1.2 (1.01– 1.5)], first visit to health centers [APR (95% CI) = 1.6 (1.3– 2.0)] and multiple provider contacts [APR (95% CI) = 5.8 (3.5– 9.6)].Conclusion: Delay in diagnosis and treatment remains a major challenge of tuberculosis control targets in pastoralist settings of Ethiopia. Efforts to expand services tailored to transhumance patterns and diagnostic capacity of primary healthcare units need to be prioritized.Keywords: patient delay, health system delay, total delay, tuberculosis, pastoralist

ObjectivesDelay in diagnosis and treatment, called total delay, could probably result in lower survival rates in breast cancer patients. This study aimed to investigate the factors associated with the comprehensive delay behaviors and to evaluate its effect on outcomes in patients with breast cancer in Dalian, a northeast city of China.MethodsA retrospective chart review was conducted using a cancer registry dataset including 298 patients. The Kaplan–Meier survival analysis was used to identify the threshold of total delay, dividing the patients into a group with significant uncertainty and a group without substantial delay. The factors associated with the significant total delay were investigated from the potential candidates, like income level and marital status, by using the chi-squared test. The difference of the clinicopathologic characteristics between the patients grouped by the significant total delay, like tumor size and lymph node metastasis, was also investigated to find out the effect of the total delay.ResultsA total of 238 charts were used for analysis. The mean age was 57.3. The median of total delays was 3.75 months. Thirty days was identified as a threshold, more than which the total delay can lead to worse survival. Patients’ marital status (p = 0.010), income levels (p = 0.003), smoking status (p = 0.031), initial visiting hospital level (p = 0.005), self-health care (p = 0.001), and self-concern about initial symptom (p ≈ 0.000) were identified as the independent predictors of the total delay. Metastasis (p ≈ 0.000) was identified as the significant result relating to the significant total delay.ConclusionsA total delay of more than 30 days predicts worse survival in breast cancer patients in Dalian. Several factors, like patients’ marital status and income levels, can be considered to be relevant to the significant total delay. We recommend that these factors be used to predict the potential patients with the significant total delay in the clinical practice.

Background: Early diagnosis and treatment of pulmonary tuberculosis (PTB) is essential for an effective control of the tuberculosis (TB) epidemic. Delayed diagnosis and treatment of TB increases the chance of complications and mortality for the patients, and enhances TB transmission in the population. Therefore, the aim of this study was to characterize patient, healthcare and total delay in diagnosing PTB and assess the effect of clinical and sociodemographic factors on the time until first contact with healthcare or reaching a PTB diagnosis.Methods: Retrospective cohort study that included active PTB patients notified in the National Tuberculosis Surveillance System (SVIG-TB), between 2008 and 2017. Descriptive statistics, Kaplan-Meier estimates, logrank test and Cox proportional hazards model were used to characterize patient, healthcare and total delay and estimate the effect of clinical and sociodemographic variables on these delays. Significance level was set at 0.05.Results: Median patient, healthcare and total delays was 37 days (Interquartile range (IQR): 19-71), 8 days (IQR: 1-32) and 62 days (IQR: 38-102), respectively. The median patient delay showed a constant increase, from 33 days in 2008 to 44 days in 2017. The median total delay presented a similar trend, increasing from 59 days in 2008 to 70 days in 2017. Healthcare delay remained constant during the study period. More than half of the PTB cases (82.9%) had a delay > 1 month between symptom onset and diagnosis. In the final Cox model, alcohol abuse, unemployment and being from a high TB incidence country were factors significantly associated with longer patient delay, while being female, having more than 45 years, oncologic and respiratory diseases were associated with longer healthcare delay. Being female, having more than 45 years and being from a high TB incidence country were associated with longer total delay.Conclusions: Patient delay and total delay have increased in recent years. Older patients, patients with alcohol problems, other comorbidities, unemployed or from countries with high TB incidence would benefit from the development of specific public health strategies that could help reduce the delay in TB diagnosis observed in our study. This study emphasizes the need to promote awareness of TB in the general population and among the healthcare community, especially at ambulatory care level, in order to reduce the gap between beginning of symptoms and TB diagnosis. [ABSTRACT FROM AUTHOR]

Background: Thirty countries with the highest tuberculosis (TB) burden bear 87% of the world's TB cases. Delayed diagnosis and treatment are detrimental to TB prognosis and sustain TB transmission in the community, making TB elimination a great challenge, especially in these countries. Our objective was to elucidate the duration and determinants of delayed diagnosis and treatment of pulmonary TB in high TB-burden countries.Methods: We conducted a systematic review and meta-analysis of quantitative and qualitative studies by searching four databases for literature published between 2008 and 2018 following PRISMA guidelines. We performed a narrative synthesis of the covariates significantly associated with patient, health system, treatment, and total delays. The pooled median duration of delay and effect sizes of covariates were estimated using random-effects meta-analyses. We identified key qualitative themes using thematic analysis.Results: This review included 124 articles from 14 low- and lower-middle-income countries (LIC and LMIC) and five upper-middle-income countries (UMIC). The pooled median duration of delays (in days) were-patient delay (LIC/LMIC: 28 (95% CI 20-30); UMIC: 10 (95% CI 10-20), health system delay (LIC/LMIC: 14 (95% CI 2-28); UMIC: 4 (95% CI 2-4), and treatment delay (LIC/LMIC: 14 (95% CI 3-84); UMIC: 0 (95% CI 0-1). There was consistent evidence that being female and rural residence was associated with longer patient delay. Patient delay was also associated with other individual, interpersonal, and community risk factors such as poor TB knowledge, long chains of care-seeking through private/multiple providers, perceived stigma, financial insecurities, and poor access to healthcare. Organizational and policy factors mediated health system and treatment delays. These factors included the lack of resources and complex administrative procedures and systems at the health facilities. We identified data gaps in 11 high-burden countries.Conclusions: This review presented the duration of delays and detailed the determinants of delayed TB diagnosis and treatment in high-burden countries. The gaps identified could be addressed through tailored approaches, education, and at a higher level, through health system strengthening and provision of universal health coverage to reduce delays and improve access to TB diagnosis and care. PROSPERO registration: CRD42018107237. [ABSTRACT FROM AUTHOR]

Abstract Background Delayed diagnosis of tuberculosis (TB) can enhance the transmission of infection and worsen prognosis. Aim To identify the risk factors of delay in the management of TB cases for early management. Patients and methods A cross-sectional analytic study was performed to assess the proportion, duration of delay, and its determinants in the diagnosis and management of TB. To assess the risk factors of delay, the sample was dichotomized into ‘delay’ and ‘nondelay’ groups taking the median total delay in the diagnosis and management of TB as a cutoff point. The study included 183 TB patients, who were registered in TB records during the study period (first of January to end of June, 2017). Data were collected by an interview questionnaire. Results Nearly half of patients (49.20%) had unacceptable total delay in the diagnosis and management of TB. The median of total delay, patient delay, and health-care system delay were 65, 14, and 20 days, respectively. Significant risk factors of total delay in the diagnosis and management of TB were not consulting the health-care provider after onset of symptoms (P=0.002), visiting initially the health facility other than the chest hospital/TB clinics (P=0.019), not consulting a chest physician initially (P=0.043), negative sputum smear (P=0.001), more than two health visits before initial diagnosis (P

Abstract Background Delayed tuberculosis (TB) diagnosis and treatment increase morbidity, mortality, expenditure, and transmission in the community. This study assessed patient and provider related delays to diagnosis and treatment of TB. Methods A cross-sectional study was conducted among 735 new adult TB cases registered between January to December 2015 in 10 woredas equivalent to districts of southwestern Ethiopia. Data were collected through face-to-face interview of patients within the first 2 months of treatment initiation. Delay in days was tracked at three intervals: between onset of symptoms and self-presentation (Patient delay), Self-presentation to treatment initiation (Provider delay) and total delay. Days elapsed beyond median were used to define the delays. Bivariate and multiple logistic regression models were fit to identify predictors of delays and statistical significance was judged at p

Currently, traffic congestion has become a serious problem in most developed cities. It is caused by an increasing number of the vehicles and the delay on arterial roads resulting in negative consequences regarding air quality, travel time, and travel safety. To reduce the traffic volume and congestion, recent solutions offer optimization of operational characteristics including the total delay and average queue length in urban intersections. Optimizing such characteristics are considered as the major breakthrough concepts of applying artificial intelligence in transportation engineering. Accordingly, the aim of this study was to develop and apply the fuzzy controller to reduce the total delay and average queue length in urban intersections. To this end, effective variables like the total delay and average queue length were simulated using the fuzzy logic controller. Then, the results were graphically simulated for the experts. Furthermore, the total delay and average queue length were compared employing the fixed-time control and fuzzy controller systems. The results indicated that in fuzzy controller system rather than the fixed-time control system, the delay and average queue length were remarkably optimized. Statistical tests also approved the efficiency of the fuzzy controller as an optimum controller system as compared to the fixed controller system. The findings of this study may help the traffic engineers and urban managers to control the traffic congestion issues based on predicting and optimizing the delay and queue length and increasing the road safety in urban intersections in the future.

Structural advancements of 5-nm node bulk fin-shaped field-effect transistors (FinFETs) without punch-through-stopper (PTS) were introduced using fully calibrated TCAD for the first time. It is challenging to scale down conventional bulk FinFETs into 5-nm technology node due to the sub-fin leakage increase. Meanwhile, bottom oxide deposition after anisotropic etching for source/drain (S/D) epi formation prevents the sub-fin leakage effectively even without the PTS doping, thus achieving better gate-to-channel controllability. Bottom oxide FinFETs also have smaller gate capacitances than do conventional FinFETs because the parasitic capacitances decrease by smaller S/D epi separated from the bottom Si layer, which reduces junction and outer-fringing capacitances. But smaller S/D epi decreases the stresses along the channel direction, and the effective widths decrease by the bottom oxide layer blocking the current paths at the bottom side of fin channels. Furthermore, increase of the interconnect resistance and capacitance parasitics down to 5-nm node diminishes the improvements of total delays as the interconnect wire length increases greatly. In spite of these drawbacks, 5-nm node bottom oxide FinFETs achieve smaller total delays than do the 7-nm node conventional FinFETs, especially for low-power applications, thus promising for the scalability of bulk FinFETs along with simple and reliable process by avoiding PTS step.

Currently, traffic congestion has become a serious problem in most developed cities. It is caused by an increasing number of vehicles and the delay on arterial roads resulting in negative consequences for air quality, travel time, and travel safety. To reduce the traffic volume and congestion, recent solutions offer optimization of operational characteristics including the total delay and average queue length in urban intersections. Optimizing such characteristics is considered as the major breakthrough concept of applying artificial intelligence to transportation engineering. Accordingly, the aim of this study was to develop and apply the fuzzy controller to reduce the total delay and average queue length in urban intersections. To this end, effective variables like the total delay and average queue length were simulated using the fuzzy logic controller. Then, the results were graphically simulated for the experts. Furthermore, the total delay and average queue length were compared employing the fixed-time control and fuzzy controller systems. The results indicated that in the fuzzy controller system rather than the fixed-time control system, the delay and average queue length were remarkably optimized. Statistical tests also approved the efficiency of the fuzzy controller as an optimum controller system as compared to the fixed controller system. The findings of this study may help the traffic engineers and urban managers to control the traffic congestion issues based on predicting and optimizing the delay and queue length and increasing the road safety in urban intersections in the future. [ABSTRACT FROM AUTHOR]

Abstract This study addresses a network-wide signal timing optimization problem with environmental concerns by a bi-objective stochastic simulation-based optimization (BOSSO) method. In this method, the global samples evaluated by costly simulation are used to build a type of surrogate model named the regressing Kriging model, which are then employed to predict bi-objectives of untested samples or filter noises from the evaluated samples. An adaptive selector is incorporated to determine which samples in the local trust-region are evaluated by costly simulation and which ones by the built regressing Kriging model. This helps to balance computational costs and accuracies of three quadratic regression models, especially when the variable dimension is high. The non-interactive role of a decision maker is taken to generate more non-dominated solutions around the desired bi-objective point. In the field experiments, an urban road network with 15 signalized and five non-signalized intersections in Changsha, China, is modeled as the simulation scenario by VISSIM. Then, the traffic simulation model is firstly calibrated from two aspects by the BOSSO method, which can well reproduce the reality. After that, the network-wide bi-objective signal timing optimization problem is also solved by the BOSSO method. Numerical results show that compared with the real-field traffic states, the total delay and vehicular emissions are reduced by at most 16.90% and 32.22% respectively under the budged number of simulations. Balance analyses also show the existence of a competing relationship between bi-objectives. Finally, the BOSSO method is validated to outperform three other counterparts (NSGA-II, BOTR and BOEGO) from various aspects. Highlights • Bi-objective stochastic simulation-based optimization (BOSSO) method is introduced. • Bi-objective calibration and signal timing problems under uncertainties are well solved. • BOSSO outperforms three other counterparts from various aspects. [ABSTRACT FROM AUTHOR]