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Background Study was carried out to find out delay from onset of symptoms and out of pocket expenditure (OOPE) until initiation of anti-TB treatment (ATT) by new Tuberculosis (TB) patients registered in public health facilities in Bengaluru. Methods Notified patients (N = 228) selected purposively were interviewed at initiation of ATT regarding number and type of facilities visited and delay in initiating ATT. OOPE was elicited separately for in- and out-patient visits, towards consultation, purchase of medicines, diagnostic tests, transportation, hospitalization and food. Dissaving or money borrowed was ascertained. Results Two-thirds of participants were 15–44 years of age and 56% were males, mean annual household income was $4357. About 75% first visited a private health facility; 68% and 87% respectively were diagnosed and started on ATT in public sector after visiting an average of three facilities and after a mean delay of 68 days; the median delay was 44 days. Of mean OOPE of $402, 54% was direct medical expenditure, 5% non-medical direct and 41% indirect. OOPE was higher for Extra-pulmonary TB compared to PTB and when number of health facilities visited before initiating treatment was >3 compared to those who visited ≤3 and when the time interval between onset of symptoms and treatment initiation (total delay) was >28 days compared to when this interval was ≤28 days. About 20% suffered catastrophic expenditure; 34% borrowed money and 37% sold assets. Conclusion Concerted efforts are needed to reduce delay and OOPE in pre-treatment period and social protection to account for indirect expenditure.

Remote sensing of water vapor using Global Navigation Satellite Systems (GNSS) is a well-established tool for weather and climate monitoring. The current challenges of GNSS meteorology are real-time performance and the inclusion of emerging GNSS, such as Galileo. We demonstrate that real-time GPS-only, Galileo-only, and GPS+Galileo solutions are consistent among each other. However, our results show that the Galileo-only solutions tend to underestimate Zenith Total Delay (ZTD) with respect to GPS. The Galileo-only real-time ZTD is less accurate as the one from GPS. The combination of both GNSS leads to a superior product. The daily solution availability increases by up to 50%, and the overall gain is 0.7% over the entire year. The accuracy improves by 3.7% to 8.5% and uncertainty is reduced by a factor of 1.5–2. A combined GPS and Galileo solution suppresses artifacts in a real-time ZTD product which otherwise would be attributed to high-frequency orbital effects.

Purpose: 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, respec-tively. 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

Introduction. Amyotrophic lateral sclerosis (ALS), usually fatal in a few years, is a neurodegenerative disorder where the diagnostic delay, although variable according to the studies, remains too long. The main objective of this study was to determine the average time to diagnose ALS and the role of each physician, general practitioner (GP), or specialist (neurologist or not) involved in the management of these patients. The secondary objective was to propose some simple schemes to quickly identify an ALS suspicion with the aim to reduce this delay. Patients and Methods. This retrospective study evaluated the diagnostic delay (and other intermediate delays) of 90 ALS patients registered in the ALS Center of Bordeaux (France) in 2013. The main clinical signs encountered (and their order of appearance) were studied. Results. The average diagnostic delay was 17 months, with a median diagnostic delay of 12 months. The average diagnostic delay was 2.7 months between the first symptoms and the first complaint to GP, followed by an additional 6.5 month delay before the patient’s first visit to a neurologist. This period could be shortened, especially if GP performed additional tests quickly (p=0.01), as the time spent consulting various specialists often extends this crucial step. Overall, diagnostic delay accounted for 40% of the total duration of the disease progression. Conclusion. In relation to total survival time, the diagnostic delay of ALS appears to be proportionately very long, sometimes longer than that observed in previous studies (because it also included the total delay to diagnostic or treatment initiation). The rapid execution of useful additional tests by the first medical doctor, often GP (with the help of a neurologist), considerably reduces the diagnostic delay. The central role of GP seems to be crucial in the management of patients with ALS. The main objective is, of course, to initiate appropriate treatment and care as soon as possible. Finally, based on our results, we also provide a short practical diagram to help nonneurologist practitioners to quickly discuss the diagnosis of ALS in case of some specific symptoms (“red flags”).

PurposeThis paper aims to increase the integrity of the planning process with the executive process by simulating the Last Planner System (LPS) technique using building information modeling.Design/methodology/approachA five-dimensional model was prepared, and after specifying the number of physical conflicts on the plans, all the scenarios of the starting points in the expert contractors’ plans were analyzed. Accordingly, the best scenario was determined by LPS technique. To assess the performance of the study, it was implemented on several tasks of a construction project.FindingsThe results of this research indicate that if this method is used in the planning process, the time conflicts between the expert contractors who are in the critical path are reduced, and the total delay of the scheduled time reaches zero. In addition, the conflicts between contractors whose suspension will cause no incentive and increase the daily cost overruns will reduce to the lowest point.Originality/valueBy simulating LPS in the planning process, time-physical conflicts are considered at the lowest point. Using this approach, conflicts are detected before the execution process, resulting in a significant reduction in the delays and cost overruns in construction projects.

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

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.

SETTING: In 2005, in response to the increasing prevalence of rifampicin-resistant tuberculosis (RR-TB) and poor treatment outcomes, Rwanda initiated the programmatic management of RR-TB, including expanded access to systematic rifampicin drug susceptibility testing (DST) and standardised treatment.OBJECTIVE: To describe trends in diagnostic and treatment delays and estimate their effect on RR-TB mortality.DESIGN: Retrospective analysis of individual-level data including 748 (85.4%) of 876 patients diagnosed with RR-TB notified to the World Health Organization between 1 July 2005 and 31 December 2016 in Rwanda. Logistic regression was used to estimate the effect of diagnostic and therapeutic delays on RR-TB mortality.RESULTS: Between 2006 and 2016, the median diagnostic delay significantly decreased from 88 days to 1 day, and the therapeutic delay from 76 days to 3 days. Simultaneously, RR-TB mortality significantly decreased from 30.8% in 2006 to 6.9% in 2016. Total delay in starting multidrug-resistant TB (MDR-TB) treatment of more than 100 days was associated with more than two-fold higher odds for dying. When delays were long, empirical RR-TB treatment initiation was associated with a lower mortality.CONCLUSION: The reduction of diagnostic and treatment delays reduced RR-TB mortality. We anticipate that universal testing for RR-TB, short diagnostic and therapeutic delays and effective standardised MDR-TB treatment will further decrease RR-TB mortality in Rwanda.

The growth in air traffic in recent decades in Europe has consequently caused aircraft delays due to insufficient capacities of airspace and airports. Primary and reactionary delays at certain European and Croatian coastal airports in 2014 are analyzed in the paper according to CODA methodology and classified according to main flight delays causes. The largest share of delay minutes at the Croatian coastal airports (75%) are related to reactionary delays, ranging from around 20% to 60% of total delay at the most congested European airports. Special emphasis is given to the analyses of rotational reactionary delay, and the results indicate that the share of reactionary delay in total delay at the Split airport is significantly higher compared to selected European airports, which may be explained by delays propagated from air traffic network and limited airport capacity. The total recorded delay at Croatian coastal airports is minor compared to total recorded delay in the European air traffic system, but delay patterns are quite similar, especially during peak summer months.

Mode shift from public transport (PT) to private car in the event of PT withdrawal can increase the level of traffic congestion in urban areas. This increase in congestion is interpreted as the congestion relief impact associated with urban PT. However, existing methods for estimating the impact of PT on relieving traffic congestion have generally assumed a fixed mode shift to car. This paper presents an enhanced method for estimating the congestion relief impact of PT by varying the mode shift to car. First, primary data from a survey conducted in Melbourne, Australia was used to develop a linear regression model for predicting the share of mode shift from PT to car. The Victorian Integrated Survey of Travel and Activity (VISTA) dataset was then applied to this model to estimate the potential mode shift for different spatial areas of Melbourne. Second, PT congestion relief impacts were estimated by contrasting the level of congestion in two scenarios: ‘with PT’ and ‘without PT’. This stage was undertaken using the Victorian Integrated Transport Model (VITM), a conventional four step model. The results show that PT operations in Melbourne contribute to reduce the number of severely congested links by more than 63%. Vehicle time travelled and total delay on the road network also reduces by around 56%.

In this study, done in the frame of the MGEX (Multi-GNSS Experiment) project, for 20 selected worldwide stations, and for the whole year of 2015, we compare zenithal total delay (ZTD) estimated values from BeiDou/GPS combined signals, to ZTD estimates from GPS-only signals, and also to ZTD estimates from the IGS analysis center CODE (CODE products), in order to assess the intrinsic accuracies of these ZTD estimates. We used the PANDA software from Wuhan university for all our data processing, with precise orbits (PPP) from the GFZ IGS analysis center. We found that the GPS-only ZTD estimates show a very good agreement with the CODE final ZTD products, but that a systematic negative bias of around 3 mm is showing up between the ZTD estimates from combined GPS/BeiDou data w.r.t. GPS-only data. This indicates that the accuracy of Beidou satellite orbits and clock errors still need to be improved w.r.t. to IGS standards.

Bus services can be seen as a way to reduce traffic congestion where they can encourage a mode shift from car. However, they can also generate negative effects on traffic flow due to stop-start operations at bus stops. This paper aims to assess the net impact of bus operations on traffic congestion in Melbourne. The methodology used to achieve this aim comprised of three main stages. First, a primary survey was conducted to determine the mode shift from bus to car when buses are unavailable. This figure was used to estimate the positive impact of buses on relieving congestion. Second, the negative impact of buses was investigated by considering the effect of bus stop operations on vehicle traffic flow using microsimulation. Finally, the net effect was estimated by contrasting congestion measures determined from a traditional four step model between two scenarios: ‘with bus’ and ‘without bus’. The results indicated that Melbourne’s bus network contributes to reduce the number of severely congested road links by approximately 10% and total delay on the road network by around 3%. The highest congestion relief impact was found in inner Melbourne with a 7% decrease in vehicle time travelled and total delay, and 16% decrease in the number of heavily congested road links. In inner areas, the level of congestion is relatively high so the mode shift from car to bus, even if not as high as middle and outer areas, have a significant effect on relieving traffic congestion. Areas for future research are suggested such as investigating the long-term effect of buses on traffic congestion.

A reservation-based intersection control algorithm was implemented for hurricane evacuation in a connected and autonomous vehicle environment. The autonomous reservation-based intersection control (AReBIC) algorithm receives and processes reservation requests from approaching vehicles in real-time and routes them free of conflict. The proposed algorithm was implemented in a simulation model of a road network in Hampton Roads, Virginia. The AReBIC algorithm outperformed the next best optimal signal control on all operational measures. The average speeds more than doubled and total delay decreased by 80%. While the total number of conflicts were comparable for AReBIC and optimal signal control, AReBIC traded the more severe crossing conflicts with less severe rear-end conflicts. The same superior performance of AReBIC was realized when transit signal priority was implemented in the study network. While the results are promising, a few practical issues should be addressed prior to any real-world implementation of reservation-based intersection control during evacuation. These issues include, latency and accuracy of communications, accommodation of pedestrians, accounting for incidents, and cybersecurity.

The article deals with the issues of improving the quality of public transport services through implementation of the concept of public transport priority. In many cities, when this concept is implemented, insufficient attention is paid to change of traffic for individual transport. Choice of optimal traffic pattern allows to ensure high speed of public transport traffic and reduce negative effect for individual transport when introducing a bus lane without expanding the roadway. The purpose of this research is to determine traffic parameters in introducing a bus lane and minimize deterioration of road traffic for individual transport. The results of simulation of road traffic in a street and road network section with a bus lane have been obtained. Based on the simulation results, the total delay time was calculated for all passengers of both individual and public transport. The results confirm the hypothesis that changing the bus lane parameters affects the road traffic parameters. Dependencies of the total delay time on the road traffic intensity of individual transport and the distance from the bus lane end to the stop line of an intersection.

In 2006, China targeted measles for elimination by 2012, but the goal was not achieved. In line with this goal, the timeliness of measles laboratory reporting should be evaluated to improve efficiency in implementing control measures. Laboratory-confirmed suspected measles cases reported to the measles surveillance system in Zhejiang Province, China, from 2009 to 2015 were collected. Three reporting periods were defined: transport duration (period from serum collected to serum received in lab), analysis duration (period from serum received to the result being reported), and total reporting duration. The median was calculated for each period. Associations between total reporting delay and other factors were accessed using logistic regression model. A total of 18,518 laboratory-confirmed suspected measles cases were collected. For transport duration, the median was within 1 day, and no variation was observed among different years. For analysis duration, the median decreased from 3 days in 2009 to 1 day in 2015. For total reporting duration, the median decreased from 5 days in 2009 to 2 days in 2015. The median of total delay was 13 days during the 7 years. The proportion of cases notified within the time limit was found to increase, indicating a tendency toward more efficient laboratory reporting. Moreover, timeliness was influenced by various external factors: reporting from CDC, reporting from counties with higher economic status, and reporting in spring were the variables associated with shorter delays. Timeliness of measles laboratory reporting has increased annually in China. Health administration departments need to pay more attention to measles laboratory surveillance in counties with lower economic status.

Objective: To find factors related with delayed diagnosis of pulmonary tuberculosis in patients presenting to the hospitals of Rawalpindi. Methods: A cross sectional observation study was carried out in Benazir Bhutto Hospital, District head quarter Hospital, Fauji Foundation Hospital, Military Hospital and Holy Family Hospital, Rawalpindi from February 2016 to September 2016. A total of one hundred ninety patients of pulmonary tuberculosis were interviewed through convenient sampling by a formulated questionnaire. Results: Mean total delay was 114.48 days whereas median total delay was 53.5 days. Mean patient delay was 33.25 days and mean health care delay was 81.23 days. On multivariate analysis unemployment was associated with patients delay whereas healthcare delay was associated with smear negative TB and patients self-realization that there is delay in diagnosis. Conclusion: This study shows that there is a long delay in the diagnosis of pulmonary tuberculosis in our country. Unemployment is main factor related to patient delay. Improving TB knowledge and socio-economic status of individuals may help in the earlier diagnosis. Adequate training of healthcare workers in diagnosing smear negative TB and improvement in health care services may also help to reduce the long healthcare delays. J Microbiol Infect Dis 2017; 7(3):119-124

When infrastructures projects are evaluated, it is not only important to evaluate them with models that represent the average daily situation, but also to evaluate them in case of irregular situations like incidents. This becomes especially relevant when various project alternatives are expected to show significantly different scores in case of incidents. Project alternatives and their road sections have different topological and geometrical characteristics. The focus of this paper is on the following characteristics: hard shoulders, the number of lanes, parallel road structures and weaving sections. The main question that this paper addresses is how these network characteristics affect both the risk of different types of incidents occurring and the effects of those incidents on the network performance (robustness). In order to answer this question, analytical examples are presented for small theoretical networks that give insight into how the selected characteristics affect the total delay caused by incidents and its dependence on the traffic volume, capacity, severity and duration of incidents. A marginal simulation based method is presented that can be used to compute the robustness effects of project alternatives, given their geometrical and topological characteristics, on a network level. A case study for an infrastructure project in the Netherlands is presented that illustrates how the robustness effects of infrastructure projects can be computed given their topological and geometrical characteristics. © 2017 Elsevier Ltd

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.

The focus of this research is on evaluating the performance of three unconventional intersection designs [Michigan U-turn (MUT), superstreet, and continuous green T-intersection (CGT)] over existing pretimed signalized intersection design along Highway 49 in the city of Charlotte, North Carolina, USA. MUT and superstreet intersection designs eliminate the left turns from side streets and replaces them with a combination of right-turn and U-turn movement. However, in the case of CGT, a separate continuous lane is provided for the through movement at one of the approaches of the intersection. Ten signalized intersections were identified along the selected study corridor. A base model was developed using Synchro/SimTraffic traffic simulation software and validated by comparing traffic volumes (provided as input vs. simulated) and through visual audits. Underperforming intersections were identified along the study corridor and were replaced with the aforementioned unconventional intersection designs. Performance measures, such as the total vehicle delay, the total delay per vehicle, and the total number of stops, were computed and compared with the existing condition. The results obtained indicate that the selected unconventional designs are not applicable at all considered intersections. The use of unconventional intersection designs could reduce the average delay per vehicle at the corridor level. However, the use of unconventional intersection designs could result in an increase in the total number of stops at the corridor level. The findings and recommendations from this research help practitioners assess the applicability of the selected unconventional intersection designs over the conventional pretimed signalized intersection design.

Background The purpose of this study was to identify the frequency, causes and estimated cost of first case operating room (OR) delays. Method A quarterly prospective review of the first cases in the OR was completed in 2018. The frequency and causes for delays were determined. Median delay time was calculated and opportunity cost was estimated based on idle labor and overtime for staffing of rooms beyond scheduled end times. Results Of 3604 first cases performed, 55% were delayed for a median 12 min (IQR 6–24 min). The patient and surgeon were responsible for 50% of the causes. Orthopedic (20%) and General (18%) Surgery accounted for the greatest percentage of total delay. A loss of 631 h resulted in an estimated cost of $311,966 for idle labor and $78,623 for nursing overtime. Conclusion Improving accountability and reducing patient-related delays will have the greatest impact on reducing first case on-time delays.

Despite the critical effect of CO 2 emissions of the aviation sector on the environment, none of the previous works on air traffic flow management (ATFM) has addressed this aspect from the perspective of the ATFM network operations. In this paper, we study this effect by proposing an ATFM bi-objective mathematical model that minimizes the total delay cost and the total CO 2 emissions. The proposed model considers ground delay, air delay, flight rerouting, speed controls, and CO2 emissions and is solved using the weighted comprehensive criterion method. The illustrative example showed that reducing CO 2 emissions by an average of 0.07% results in an average of 1.2% increase in the total delay cost. The consideration of CO 2 emissions leads to a solution that favors ground holding rather than air holding or rerouting to longer paths.

With the continuous expansion of urban rapid transit networks, disruptive incidents—such as station closures, train delays, and mechanical problems—have become more common, causing such problems as threats to passenger safety, delays in service, and so on. More importantly, these disruptions often have ripple effects that spread to other stations and lines. In order to provide better management and plan for emergencies, it has become important to identify such disruptions and evaluate their influence on travel times and delays. This paper proposes a novel approach to achieve these goals. It employs the tap-in and tap-out data on the distribution of passengers from smart cards collected by automated fare collection (AFC) facilities as well as past disruptions within networks. Three characteristic types of abnormal passenger flow are divided and analyzed, comprising (1) “missed” passengers who have left the system, (2) passengers who took detours, and (3) passengers who were delayed but continued their journeys. In addition, the suggested computing method, serving to estimate total delay times, was used to manage these disruptions. Finally, a real-world case study based on the Beijing metro network with the real tap-in and tap-out passenger data is presented.

We introduce the decision support tool PANDA (Passenger Aware Novel Dispatching Assistance). Our web-based tool is designed to provide train dispatchers with detailed real-time information about the current passenger flow and the multi-dimensional impact of waiting decisions in case of train delays. After presenting the algorithmic background and PANDA’s main features, we show how it can be utilized in a typical use case scenario for train dispatchers. Besides its practical value for train dispatchers, the framework can be used to systematically study scientific questions. Exemplarily, we use our software to experimentally analyse the influence of waiting decisions on realistic passenger flows of Deutsche Bahn. In a first experiment, we evaluate PANDA’s potential benefit for passengers. Our findings indicate that a remarkable reduction in total delay might be possible in comparison to current practice. In two additional experiments, we investigate the timing aspect of waiting decisions. Our observations suggest that the timing of waiting decisions is of crucial importance and that a carefully implemented early rerouting strategy has a significant potential to reduce resulting delays of passengers.

In order to broadcast an alert message from the accident site to the control center as soon as possible, the roadside units (RSUs) act as the critical component in vehicular ad hoc networks (VANETs). It is not possible to make a pervasive RSU deployment due to the huge cost and market requirement. Hence, how to deploy a minimum number of RSUs in a given region becomes a challenge problem. In this paper, we present an analysis for the total delay of broadcasting alert messages in VANETs along highways. Based on the analysis, the relationship between optimal number of RSUs with the highway distance is given. Moreover, the experiment results verifies the delay analysis and the optimization of RSUs deployment.

SETTING The diagnosis and treatment of tuberculosis (TB) in India are characterized by heavy private-sector involvement. Delays in treatment remain poorly characterized among patients seeking care in the Indian private sector. OBJECTIVE To assess delays in TB diagnosis and treatment initiation among patients diagnosed in the private sector, and pathways to care in an urban setting. DESIGN Cross-sectional survey of 289 consecutive patients diagnosed with TB in the private sector and referred for anti-tuberculosis treatment through a public-private mix program in Chennai from January 2014 to February 2015. RESULTS Among 212 patients with pulmonary TB, 90% first contacted a formal private provider, and 78% were diagnosed by the first or second provider seen after a median of three visits per provider. Median total delay was 51 days (mean 68). Consulting an informal (rather than formally trained) provider first was associated with significant increases in total delay (absolute increase 22.8 days, 95%CI 6.2-39.5) and in the risk of prolonged delay >90 days (aRR 2.4, 95%CI 1.3-4.4). CONCLUSION Even among patients seeking care in the formal (vs. informal) private sector in Chennai, diagnostic delays are substantial. Novel strategies are required to engage private providers, who often serve as the first point of contact.

We propose a novel floorplanning algorithm for 3D ICs with through-silicon vias (TSVs) that directly optimizes delay due to wires and TSVs. We include the non-negligible impact of area occupied by TSVs, perform nets-to-TSVs assignment, and use physical dimensions of TSVs and wires for delay calculations. Our floorplanning is based on co-placement of TSV islands with circuit blocks and is performed under fixed-outline constraints. The total delay is a direct optimization goal in the presented delay-aware 3D floorplanning and accounts for the RC delay impact of TSVs on the delay of each individual net during the nets-to-TSVs assignment. Therefore, compared to traditional wirelength-aware floorplanning, which separately minimize wirelength and the number of TSVs, the proposed approach results in more effective delay minimization. Our experimental results show improved solution quality with up to 9 % shorter wirelength and an average 40 % reduction in the number of TSVs as compared to most recent publications. Total delay reduces between 10 and 12 % when the delay, instead of wirelength and the number of TSVs separately, is minimized.

To obtain a wide range of high-precision time-delay controllable devices, a 100-µm-thick nematic liquid crystal (LC) cell was fabricated using the LC HTD028200-200. Factors influencing the delay calibration accuracy of LC variable retarders (LCVRs) were analyzed theoretically and experimentally. Subsequently, within the total voltage tuning range of 0–5 V, the LCVR had a delay of 4.977–97.404 fs, total delay range of 90 fs, tuning accuracy of ± 0.216 f s , and tuning resolution of 0.128 fs. This device will play an important role in spectral imaging.

This paper presents an initial implementation of an autonomous Urban Air Mobility network management and aircraft separation service for urban airspace that does 1) departure and arrival scheduling across the network, 2) continuous trajectory management to ensure safe separation between aircraft, and 3) seamless integration with traditional operations. The highly-autonomous AutoResolver algorithm developed for traditional aviation was extended to provide these capabilities. An evaluation of this initial implementation was conducted in fast-time simulations using a dense, two-hour traffic scenario with Urban Air Mobility aircraft flying between a network of 20 vertiports in the Dallas-Fort Worth metroplex. When the spatial separation was reduced from 0:3nmi to 0:1nmi, the total de- lay decreased by 7:3%; when the temporal separation was reduced from 60s to 45s, the total delay decreased by 28:4%. The total number of conflict resolutions decreased by 26% and 17%, respectively. Furthermore, when a scheduling horizon greater than the duration of UAM flights was used (50min), most conflicts were resolved pre-departure producing ground delay. By comparison, when a shorter scheduling horizon was used (8min), most conflicts were resolved post-departure generating airborne delay. For all scheduling and separation constraints tested, AutoResolver prevented loss of separation from occurring. Urban Air Mobility operations have the ability to revolutionize how people and goods are transported and this paper presents initial research focusing on the high levels of autonomy required for an airspace system capable of scaling to handle significantly higher densities of aircraft.

This paper presents FPGA based implementation of a hardware firewall. This is characterized by filtering of high speed packet of length 512 bits based on the list of allowed Internet Protocols. Designed FPGA hardware firewall consists of input register of 512 bits and output register of 512 bits. When the first packet enters the hardware firewall it takes 512 clock cycles to completely fit in input register. Many comparison statements are implemented as per the number of allowed IPs and then the matched packet will be given out through output register of 512 bits. Thus the first packet experiences total delay of 1024 clock cycles and by the time first packet comes out through output register the next packet enters in the input register at the same time and the process continues. The designed architecture is so has to achieve same processing time despite increasing the number of rules. The implementation results show that hardware based firewall is faster as compared to conventional software firewall.

Purpose. To examine causes as well as extent of delay in diagnosis and treatment of primary open angle glaucoma patients in a sample of Egyptians.Patients and Methods. 440 patients with primary open angle glaucoma were interviewed to evaluate delay in their diagnosis and treatment. The extent and cause of delay were investigated. The total delay interval, if any, was correlated with socioeconomic and other factors.Results. The median total delay was one year, with 50% of patients having a total delay of 1 year or less, of which 25% exhibited zero total delay. 25% of patients had a delay ranging from 1 to 3 years, and 25% had a total delay ranging from 3 to 27 years. Diagnostic delay accounted for 43.03% of cases. Longer delays were met in patients with certain socioeconomic factors. Patients with a positive family history of glaucoma displayed shorter delay periods.Conclusion. Significant delay in the diagnosis and treatment of glaucoma was found. Poor socioeconomic status seems to hinder timely diagnosis and treatment of POAG. Certain socioeconomic factors seem to correlate with the extent of delay. More effort is thus needed to subsidize the cost of investigations and treatment for glaucoma patients.

To further improve the utilization rate of railway tracks and reduce train delays, this paper focuses on developing a high-efficiency train routing and timetabling approach for double-track railway corridors in condition that trains are allowable to travel on reverse direction tracks. We first design an improved switchable policy which is rooted in the approaches by Mu and Dessouky (2013), with the analysis of possible delays caused by different path choices. Then, three novel integrated train routing and timetabling approaches are proposed on the basis of a discrete event model and different dispatching rules, including no switchable policy (No-SP), Mu and Dessouky (2013)’s switchable policy (Original-SP) and improved switchable policy (Improved-SP). To demonstrate the performance of the proposed approaches, the heterogeneous trains on Beijing–Shanghai high speed railway are scheduled by aforementioned approaches. The case studies indicate that in comparison to No-SP and Original-SP approaches, respectively, the Improved-SP approach can reduce the total delay of trains up to 44.44% and 73.53% within a short computational time. Moreover, all of the performance criteria of the Improved-SP approach are usually better than those of other two approaches.

In recent years, resonant cycles have emerged as a new principle in signal coordination. Resonant cycles were originally associated with cycle lengths that resulted in good progression over a range of traffic volumes. Several studies documented the potential benefits of this new principle. In this research, “resonant cycles” are defined as cycle lengths that are robust over a range of traffic volumes on two-way arterials. However, resonant cycles may not always exist on traffic corridors, depending on their operational and geometric factors, and the impact of these factors is not well understood. To examine these conditions more closely, this paper provides a comprehensive analysis of resonant cycles. Geometric and operational traffic data obtained from two corridors were used. Resonant cycles were observed on both corridors; the benefits resulted in reductions of approximately 8% in the total delay and 19% in the number of stops when compared with the critical intersection method. The geometric and operational variables that permitted resonant cycles were identified through a macroscopic model. The results indicated that resonant cycles could easily be found on these two corridors under low-volume scenarios. When moderate-volume conditions occurred, certain combinations of geometric and operational traffic variables supported resonant cycles. In contrast, cross-street volumes that were similar in magnitude to the volumes of the main street tended to remove the cycle resonance for moderate traffic volumes. When a microscopic model was used to estimate optimal cycle lengths, the range of traffic volumes under a resonant cycle was reduced.

■ Work expands the scope of current EU/US performance benchmarking efforts ■ Developed an analytical framework ▪ Verified a mapping of the ICAO derived ATFM framework to the US and European ATM systems. ▪ Developed a taxonomy of TMI types consisting of five levels of TMIs ascribed to their role in the strategic to tactical phases of ATFM to support type-by-type comparison. ▪ Identified suitable and compatible data archives to support these comparisons. ■ Initial Results ▪ While total delay between the two regions does not differ considerably, they apply conceptually different traffic management strategies. ▪ The data suggest that delay TMIs in the US are used more often to manage airport capacity imbalances, whereas Europe is more focused on managing the airspace. ▪ TMIs in the US are smaller in number and target a smaller number of flights which are severely impacted, while in Europe the number of initiatives is larger and the impact of such initiatives is spread over a significantly higher number of airspace users with an average delay per delayed flight that is 50% less than that in the US. ▪ The much smaller number of TMIs used in the US are more apt to be re-evaluated once initiated, whereas initiatives in Europe are less likely to be shortened.

We conducted a cross-sectional survey in 2012 in 12 selected provinces and prefectures in Morocco to determine consultation delay (patient delay), diagnosis delay and treatment delay (health system delays), and factors relating to these delays. The sample included 250 eligible and consenting newly diagnosed smearpositive pulmonary tuberculosis patients who were interviewed at the time of their registration within Diagnosis of Tuberculosis and Respiratory Diseases Reference Centers (CDTMR) or Integrated Health Centers (CSI) using a pretested and structured questionnaire. The median total delay was 46 days [inter-quartile interval (IQI) = 29-84 days]. Patient delay (median = 20; IQI = 8-47 days) was higher than health system delay (median=15; IIQ = 7-35 days). Being illiterate, thinking symptoms will disappear by themselves; having financial constraints and feeling fear of diagnosis or social isolation were associated with patient delay. Consulting first in the private sector or having 3 or more consultations before diagnosis was associated with health system delay.محدِّدات تأخُّر الاستشارة والتشخيص والمعالجة لدى مرضى السل الرئوي الجدد إيجابيِّي اللطاخة في المغرب: دراسة مستعرضةمحمد أكريم، كنزة بناني، أمينة الصلبي، محمد صغيار، أنّا ليكوس، عبد الرحمن بنمأمون، عمر منزهي، عبد الرحمان معروفيقد أجرى الباحثون دراسة مستعرضة في عام 2012 في 12 محافظة ومقاطعة مختارة في المغرب لتحديد تأخُّر الاستشارة (تأخُّر المريض)، وتأخُّر التشخيص وتأخُّر المعالجة (تأخيرات النظام الصحي)، والعوامل المتعلقة بهذه التأخيرات. وقد شملت العيِّنة 250 مريضاً – انتُخِبوا وتم الحصول على موافقتهم – ممن شُخِّص لديهم حديثاً سلٌّ رئويٌ إيجابيِّ اللطاخة. وتمت مقابلتهم عند تسجيلهم في المراكز المرجعية لتشخيص السل والأمراض التنفسية أو في مراكز الرعاية الصحية المتكاملة، باستخدام استبيان مختبرَ مسبقاً ومنظَّم. فكان متوسط التأخُّر الكلي 46 يوماً [الفاصل الربعي 84-29 = (IQI) يوماً]. وكان تأخُّر المريض المريض (الوسطي =20، 8-47 = IQI يوماً) أعلى من تأخير النظام الصحي المريض (الوسطي =15، 5-37 = IQI يوماً). ولكون بعض المرضى من غير المتعلمين، فقد ظنوا أن الأعراض ستختفي من تلقاء ذاتها. وكان هناك تَرَابُط بين وجود معوقات مالية والشعور بالخوف من التشخيص أو من العزلة الاجتماعية وبين تأخُّر المريض، وتَرَابُط بين إجراء استشارة في القطاع الخاص أولاً أو وجود 3 استشارات أو أكثر قبل التشخيص وبين تأخر تشخيص النظام الصحي.Déterminants des délais de consultation, de diagnostic et de traitement pour les nouveaux patients tuberculeux pulmonaires à microscopie positive au Maroc : étude transversale.Nous avons conduit en 2012 une étude transversale dans une sélection de 12 provinces/préfectures au Maroc pour déterminer les délais de consultation (délai patient), de diagnostic et de mise sous traitement (délai système de santé) chez les nouveaux cas de tuberculose pulmonaire à microscopie positive et les facteurs en relation avec ces délais. L’échantillon comprenait 250 patients, éligibles et consentants, qui ont été interviewés lors de leur enregistrement aux Centres de Diagnostic de la Tuberculose et des Maladies Respiratoires (CDTMR) ou aux Centres de Santé Intégrés (CSI), en utilisant un questionnaire structuré et prétesté. Le délai total médian est de 46 jours (intervalle interquartile [IIQ] : 29-84 jours). Le délai patient (médiane : 20 jours ; IIQ : 8-47) est supérieur au délai système de santé (médiane : 15 jours ; IIQ : 7-35). Être analphabète, croire à la disparition spontanée des symptômes, avoir des contraintes économiques ou peur du diagnostic et de l’isolement social sont associés au délai patient. Consulter en premier dans le secteur privé ou faire trois consultations au moins avant le diagnostic sont associés au délai système de santé.

Setting state of bus stop affects the efficiency of the entire road system. Through discussing bus bay stop’s width, length and distance to intersection, a microscopic simulation was conducted in this paper. With a certain bus frequency, the total delay time of vehicles was analyzed under different road traffic in different forms of Da Yanta Bus Station in Xi’an. The results show that setting bus bay stops on the secondary roads which have large traffic flow can significantly reduce delay time, and can provide references for urban road design.

Objective To systematically review Indian literature on delays in tuberculosis (TB) diagnosis and treatment. Methods We searched multiple sources for studies on delays in patients with pulmonary TB and those with chest symptoms. Studies were included if numeric data on any delay were reported. Patient delay was defined as the interval between onset of symptoms and the patient's first contact with a health care provider. Diagnostic delay was defined as the interval between the first consultation with a health care provider and diagnosis. Treatment delay was defined as the interval between diagnosis and initiation of anti-tuberculosis treatment. Total delay was defined as time interval from the onset of symptoms until treatment initiation. Results Among 541 potential citations identified, 23 studies met the inclusion criteria. Included studies used a variety of definitions for onset of symptoms and delays. Median estimates of patient, diagnostic and treatment delay were respectively 18.4 (IQR 14.3-27.0), 31.0 (IQR 24.5-35.4) and 2.5 days (IQR 1.9-3.6) for patients with TB and those with chest symptoms combined. The median total delay was 55.3 days (IQR 46.5-61.5). About 48% of all patients first consulted private providers; an average of 2.7 health care providers were consulted before diagnosis. Number and type of provider first consulted were the most important risk factors for delay. Conclusions These findings underscore the need to develop novel strategies for reducing patient and diagnostic delays and engaging first-contact health care providers.

This paper aims to find an optimal balanced schedule with the least delay-ratio (i.e., the ratio of the total delay time and the total free-run time) by considering the impacts of the train velocity. A rigorous optimization model is proposed under the consideration of feasible speed constraint for finding the optimal velocity for each train on the railway line. To obtain an approximately optimal scheduling strategy, a combination of the improved TAS (ITAS) method and the genetic algorithm (GA), called GA-ITAS method, is in particular proposed to effectively solve the proposed model. The results of numerical experiments demonstrate the efficiency and effectiveness of the proposed approaches.

This work presents an improved dead-beat predictive current controller for grid-tie inverters that addresses issues related to implementation delays. The total delay is composed of the integer computational delay and a fractional delay, which is taken into account in the design of the controller algorithm, to improve its performance and robustness. The control strategy, based on a model that includes these delays, employs state feedback and a prediction observer in order to obtain a true two-sample ripple free dead-beat response. System robustness can be adjusted with an appropriate selection of the location of the observer poles, at the expense of reducing control bandwidth. The proposed control scheme is both simple and computationally efficient since only few operations are required to include the delay in the algorithm. Experimental results show an improvement of the dynamic response even when mismatch in the load-inductance value estimation occurs. Fil: Fischer, Jonatan Roberto. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Departamento de Electrónica. Laboratorio de Instrumentación y Control; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: González, Sergio Alejandro. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Departamento de Electrónica. Laboratorio de Instrumentación y Control; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Herrán, Mario Alejandro. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Departamento de Electrónica. Laboratorio de Instrumentación y Control; Argentina Fil: Judewicz, Marcos. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Departamento de Electrónica. Laboratorio de Instrumentación y Control; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Carrica, Daniel Oscar. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Departamento de Electrónica. Laboratorio de Instrumentación y Control; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina

BACKGROUND AND OBJECTIVE: Pediatric endoscopic procedures are essential in the evaluation and treatment of gastrointestinal diseases in children. Although pediatric endoscopists are greatly interested in increasing efficiency and through-put in pediatric endoscopy units, there is scarcely any literature on this critical process. The goal of this study was to improve the timeliness of pediatric endoscopy procedures at Children’s Hospital at Montefiore. METHODS: In June 2010, a pediatric endoscopy quality improvement initiative was formed at Children’s Hospital at Montefiore. We identified patient-, equipment-, and physician-related causes for case delays. Pareto charts, cause and effect diagrams, process flow mapping, and statistical process control charts were used for analysis. RESULTS: From June 2010 to December 2012, we were able to significantly decrease the first case endoscopy delay from an average of 17 to 10 minutes (P < .001), second case delay from 39 to 25 minutes (P = .01), third case delay from 61 to 45 minutes (P = .05), and fourth case delay from 79 to 51 minutes (P = .05). Total delay time decreased from 196 to 131 minutes, resulting in a reduction of 65 minutes (P = .02). From June 2010 to August 2011 (preintervention period), an average of 36% of first endoscopy cases started within 5 minutes, 51% within 10 minutes, and 61% within 15 minutes of the scheduled time. From September 2011 to December 2012 (postintervention period), the percentage of cases starting within 5 minutes, 10 minutes, and 15 minutes increased to 47% (P = .07), 61% (P = .04), and 79% (P = .01), respectively. CONCLUSIONS: Applying quality improvement methods and tools helped improve pediatric endoscopy timeliness and significantly decreased total delays.

The environmental effects and network performance of mixed traffic, consisting of micro-cars and conventional cars, on a small network are investigated using microscopic simulations. After calibrating the simulation model, the effects of three assumptions concerning micro-car speeds are investigated using the model. First, the parameters needed for network performance evaluation are determined iteratively. The power required to meet total travel demand is then computed to predict emissions. A higher ratio of micro-cars in the traffic reduces emissions, as does a lower micro-car speed. To investigate travel efficiency, the main parameters used are average speed, total travel time and total delay time. The results suggest that a higher ratio of micro-cars has a positive effect on the network when their speed is the same as or a slightly lower than that of conventional cars, while a higher ratio of micro-cars has a negative effect when their speed is close to the average traffic speed of the base model. To obtain a suitable balance between desired environmental effects and road network performance, we recommend that the desired speed of micro-cars be set to 40–45 km/h on a small urban traffic network.

Background: Reducing treatment delay improves outcomes in breast cancer. The aim of this study was to determine factors influencing patient- and system-related delays in commencing breast cancer treatment in different countries. Methods: A total of 6588 female breast cancer patients from 12 countries were surveyed. Total delay time was determined as the sum of the patient-related delay time (time between onset of the first symptoms and the first medical visit) and system-related delay time (time between the first medical visit and the start of therapy). Results: The average patient-related delay time and total delay time were 4.7 (range: 3.4–6.2) weeks and 14.4 (range: 11.5–29.4) weeks, respectively. Longer patient-related delay times were associated with distrust and disregard, and shorter patient-related delay times were associated with fear of breast cancer, practicing self-examination, higher education level, being employed, having support from friends and family and living in big cities. The average system-related delay time was 11.1 (range: 8.3–24.7) weeks. Cancer diagnosis made by an oncologist versus another physician, higher education level, older age, family history of female cancers and having a breast lump as the first cancer sign were associated with shorter system-related delay times. Longer patient-related delay times and higher levels of distrust and disregard were predictors of longer system-related delay times. Conclusions: The delay in diagnosis and treatment of breast cancer remains a serious problem. Several psychological and behavioural patient attributes strongly determine both patient-related delay time and system-related delay time, but their strength is different in particular countries.

In order to solve the time synchronization problem in tandem hot strip line, the traditional algorithm of time synchronization was analyzed, and the server-client mode was compared with the broadcast mode using multithread technology, then the present paper improved the broadcast mode to improve its precision. The new method can estimate total delay including clock offset and network transmission time. A simple, easy and little loading time synchronization method was designed for the distributed process control system of tandem hot strip line. The new method was applied in domestic some tandem hot strip line successfully which showed that it could meet the demands of process control system with little expenses, simple structure and high precision.

The strategy used by participants was studied when making movements in a Fitts movement paradigm with transmission delay between control input and display output. Fitts' law in the modified form developed by E. R. Hoffmann (1992) gave an excellent description of the data. Movement time could also be expressed as a function of the total delay time (number of submovements × transmission delay) and Fitts' index of difficulty (ID). Two types of submovement were identified, being step and drag forms. The number of step submovements was the most important in determining movement time. These were related to a move-and-wait strategy used by participants. Number of submovements increased with the level of ID and transmission delay and was linearly related to the ID and product of ID by transmission delay.

We investigate the traversal of electromagnetic pulses through dispersive media with negative refractive index in such a way that no resonant effects come into play. It has been verified that for evanescent waves, the definitions of the group delay and the reshaping delay times get interchanged in comparison to the propagating waves. We show that for a negative refractive index medium (NRM) with e(ω)=μ(ω), the reshaping delay time identically vanishes for propagating waves. The total delay time in NRM is otherwise contributed by both the group and the reshaping delay times, whereas for the case of broadband pulses in NRM the total delay time is always subluminal.

International audience; Air Transportation contributes in more than 2% of the total global emissions. In this paper, we formulate the air traffic flow management (ATFM) problem as a bi-objective mixed integer linear programming model that minimizes the carbon dioxide (CO 2) emissions and the total delay cost. The model is solved using a Pareto-based scalarization technique called the weighted comprehensive criterion method. A numerical example is used to illustrate the effect of considering CO 2 emissions on the ATFM network. A Pareto front is developed to illustrate the trade-off between CO 2 emissions and the total delay costs. The results showed that reducing 1 kg of CO 2 emissions comes at a delay cost of 1.22 €. This result can be beneficial for decision makers in determining penalty values and setting aviation emission policies.

One of the most straightforward short term policies to mitigate urban traffic congestion is control through traffic lights at a single junction or network level. Existing approaches for single junction Signal Setting Design (SSD) can be grouped into two classes: Stage-based or Phase-based methods. Both these approaches take the lane marking layouts as exogenous inputs, but lane-based optimisation method may be found in literature, even though for isolated signal-controlled junctions only. The Network Signal Setting Design (NSSD) requires that offsets are introduced; a traffic flow model is also needed to compute total delay. All existing methods for NSSD follow a stage-based approach; these methods do not allow for stage matrix optimisation: it is shown that explicit enumeration of stage sequences is only practicable for very small networks. This paper focuses on Network Signal Setting Design introducing the so-called scheduled synchronisation that includes green scheduling, green timing and coordination into one optimisation problem. The paper proposes a stage-based method to solve such a problem, as an extension of the synchronisation method and the traffic flow model proposed in Cantarella et al. (2015): first a set of candidate stages is defined for each junction, then the stage sequences, the stage lengths and the offsets are optimised all together. To the authors’ knowledge, no other one-step optimisation method is available in literature for scheduled synchronisation. Results of the proposed method to a small network were compared with those from explicit enumeration of all stage sequences; results for a larger network are also discussed.

Delay analysis providing an alternative physical explanation on carrier transport, which may be more applicable to high electron mobility transistor (HEMT) channels with moderate carrier mobilities, has been applied to enhancement-mode (E-mode) and depletion-mode (D-mode) InAlN/AlN/GaN HEMTs with comparable f T at room and cryogenic temperatures. It was found that the speed of the E-mode HEMTs with 33-nm long T-gate is dominated by parasitic delays, >40% of the total delay; channel mobility might have degraded due to gate recess.

Train re-scheduling problems are popular among researchers who have interest in the railway planning and operations fields. Deviations from normal operation may cause inter-train conflicts which have to be detected and timely resolved. Except for very few applications, these tasks are usually performed by train dispatchers. Due to the complexity of re-scheduling problems, dispatchers utilize some simplifying rules to resolve conflicts and implement their decisions accordingly. From the system effectiveness and efficiency point of view, their decisions should be supported with appropriate tools because their immediate decisions may cause considerable train delays in future interferences. Such a decision support tool should be able to predict overall implications of the alternative solutions. Genetic algorithms (GAs) for conflict resolutions were developed and evaluated against the dispatchers’ and the exact solutions. The comparison measures are the computation time and total (weighted) delay due to conflict resolutions. For benchmarking purposes, artificial neural networks (ANNs) were developed to mimic the decision behavior of train dispatchers so as to reproduce their conflict resolutions. The ANN was trained and tested with data extracted from conflict resolutions in actual train operations in Turkish State Railways. The GA developed was able to find the optimal solutions for small sized problems in short times, and to reduce total delay times by around half in comparison to the ANN (i.e., train dispatchers).

With in-vehicle automation and vehicle connectivity gaining momentum, cooperative adaptive cruise control (CACC) systems are expected to enter the market in the near future. Given that the number of roundabouts in the United States has increased significantly, this research effort investigated the potential benefits of the use of CACC systems and vehicle-to-infrastructure connectivity to optimize the trajectories of vehicles approaching a single-lane roundabout. The optimization ensures that vehicles can enter the roundabout when gaps in the circulating roadway are available. The proposed idea is generally similar to the concept of metering single-lane entrance ramps. The system is simulated on a single-lane roundabout for different traffic demands and CACC market penetration levels. The study demonstrates that CACC systems can produce savings in total delay and fuel consumption levels of up to 80% and 40%, respectively, relative to the levels for traditional roundabout control. Further benefits are also achievable if one considers the potential to reduce the time headway between CACC-equipped vehicles and thus increase lane capacity.

The research presented in this paper analyzes the merging version of the continuous green T-intersection (CGT), an alternative intersection design–control that allows certain lanes along the main street to bypass three-way intersections, with side street traffic merging onto the main road. A comprehensive model encompassing 2,445 unique combinations of intersection conditions was run to compare the merging CGT with the standard three-way signalized intersection. The study demonstrated significant intersection improvements over conventional traffic signal timing. Specifically, significant benefits were observed for the merging CGT in total delay, fuel usage, and emissions of hydrocarbons, carbon monoxide, oxides of nitrogen, and carbon dioxide. In addition, an economic analysis showed significant user savings associated with CGT control. Because of higher traffic volumes on the main road than the side street, savings for vehicles on the main street outweighed any costs associated with side street traffic merging into the main street flow. These findings strongly support the decision to implement the merging CGT over standard three-way signalized intersection control. Before this work, no comprehensive model that considered the environmental and economic implications of any form of the CGT had been published, and no comprehensive model specifically focused on the merging version of the CGT.