To see the other types of publications on this topic, follow the link: In-transit failure.
Journal articles on the topic 'In-transit failure'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 journal articles for your research on the topic 'In-transit failure.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse journal articles on a wide variety of disciplines and organise your bibliography correctly.
1
Zhao, Yuan, and Xiaobing Ding. "The Research on Delay Propagation of Urban Rail Transit Operation under Sudden Failure." Journal of Advanced Transportation 2021 (May 14, 2021): 1–10. http://dx.doi.org/10.1155/2021/8984474.
Full textAbstract:
With the increase and extension of urban rail transit lines, networked operation has become an inevitable trend of rail transit operations. Once an emergency occurs, it will cause operational delays; in serious cases, it may further lead to group safety incidents. Firstly, the sudden failure of rail transit is defined, statistical calculation is made according to the accumulated failure data, and then the sudden failures and average processing time are quantitatively calculated. Secondly, the time delay and propagation under the state of sudden failure are analyzed, on the basis of which the propagation and dissipation of time delay based on the single station failure cellular automata model and SIR model network based on multistation fault delay propagation are constructed. Finally, the reliability and accuracy of the model are verified by a case of rail transit in a city. The scheme in this paper can be used to estimate the scope of time and space delay under the sudden failure of rail transit and can provide the basis for the adjustment of traffic organization scheme and evacuation of passenger flow under the sudden failure.
2
Cox, Peter. "Data in Transit." ITNOW 62, no. 1 (2020): 60–61. http://dx.doi.org/10.1093/itnow/bwaa028.
Full textAbstract:
Abstract Peter Cox, CEO and Founder of UM Labs, explores VoIP and messaging systems and explains why organisations need to ensure high levels of security around data-in-transit, warning that failure to do so may lead to GDPR compliance issues.
3
Gabriel, S. K. Akakpo, Kwame Eyram, S. A. Gladstone-Bright P., and S. Ewedji Christabel. "Identification of Risks of Failure of Pneumatic Tyres of Passenger Vehicles in Ghana." International Journal of Social Science and Humanities Research 10, no. 2 (2022): 170–81. https://doi.org/10.5281/zenodo.6542318.
Full textAbstract:
<strong>Abstract:</strong> In-transit failures of pneumatic tyres of heavy vehicles such as passenger buses, which ply some major intercity highways in Ghana remain a great source of worry in Ghanaian transportation system. The study seeks to identify major causes of the in-transit failures of pneumatic tyres of heavy vehicles, and how to prevent such failures. Five thousand (5000) pneumatic tyres were sampled using a simple random sampling method and idiosyncrasies of some drivers of these heavy passenger buses were observed. The data gathered was analyzed using cross tabulation and simple statistics. It was found out that tubeless pneumatic tyres used by these heavy passenger buses have higher risk of failure than the tubed ones. In addition, the study revealed that some brands of tyres have higher failure rates than others under conditions such as nature of road, loading capacity and tyre maintenance. The study recommends that tyre usage rules should be complied with in order to reduce the risk of failure of pneumatic tyres among passenger vehicles. <strong>Keywords:</strong> Risk, in-transit failure, pneumatic tyre, transportation, automobile, passenger vehicles, road safety. <strong>Title:</strong> Identification of Risks of Failure of Pneumatic Tyres of Passenger Vehicles in Ghana <strong>Author:</strong> Gabriel S. K. Akakpo, Eyram Kwame, P. S. A. Gladstone-Bright, Christabel S. Ewedji <strong>International Journal of Social Science and Humanities Research </strong> <strong>ISSN 2348-3156 (Print), ISSN 2348-3164 (online)</strong> <strong>Vol. 10, Issue 2, April 2022 - June 2022</strong> <strong>Page No: 170-181</strong> <strong>Publisher: Research Publish Journals </strong> <strong>Website: www.researchpublish.com</strong> <strong>Published Date: 12-May-2022</strong> <strong>DOI: https://doi.org/10.5281/zenodo.6542318</strong> <strong>Paper Download Link (Source): </strong> <strong>https://www.researchpublish.com/papers/identification-of-risks-of-failure-of-pneumatic-tyres-of-passenger-vehicles-in-ghana</strong>
4
Hu, Junhong, Mingshu Yang, Yunzhu Zhen, and Wenling Fu. "Node Importance Evaluation of Urban Rail Transit Based on Signaling System Failure: A Case Study of the Nanjing Metro." Applied Sciences 14, no. 20 (2024): 9600. http://dx.doi.org/10.3390/app14209600.
Full textAbstract:
Assessing the importance of nodes in urban rail transit systems helps enhance their ability to respond to emergencies and improve reliability in view of the fact that most of the existing methods for evaluating the importance of rail transit nodes ignore the disturbance effect of signaling system failures and are unable to objectively identify critical stations in specific disturbance scenarios. Therefore, this paper proposed a method for evaluating the importance of urban rail transit nodes in signaling system failure scenarios. The method was based on the research background of the signaling system failure that occurs most frequently and analyzed the network failure mechanism after the occurrence of a disturbance. The node importance evaluation indices were selected from the network topology and network operation performance in two aspects. The variation coefficient–VIKOR method was employed to comprehensively assess the significance of urban rail transit stations during signaling system failures. The Nanjing Metro network was also used as an example to evaluate the importance of network stations. The results showed that under the attack method of signaling system failure, most ECC and interlocking stations experienced significantly higher network performance losses compared to the original attack method, and a few interchange stations showed smaller performance losses. The critical stations identified based on the proposed method are mainly distributed in the passenger flow backbone of the Nanjing Metro and were constructed in the early stage; of these, 85% are ECC stations or interlocking stations, which are easily neglected in daily management, in contrast to interchange stations with heavy passenger flow. The results of this study can provide an important reference for the stable operation and sustainable construction of urban rail transit.
5
Lefebvre, Hervé P., Jean-Pierre Ferré, A. David J. Watson, et al. "Small bowel motility and colonic transit are altered in dogs with moderate renal failure." American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 281, no. 1 (2001): R230—R238. http://dx.doi.org/10.1152/ajpregu.2001.281.1.r230.
Full textAbstract:
Although gastrointestinal complications are common in patients with renal disease, the effects of renal dysfunction on bowel motility and gut transit times are not well known. We assessed gastrointestinal electromyographic activity, gastric emptying rate, orocolonic transit time, oroanal transit time, and xylose absorption before and after surgically inducing a 66% decrease in glomerular filtration rate in dogs. Moderate renal failure induced no gross or microscopic gastrointestinal lesions but caused a 16–42% increase in gastrointestinal motility indexes. We found a 24% decrease in the propagation velocity of the myoelectrical migrating complex in the duodenojejunal segment, a 30% decrease in phase I duration in duodenal and jejunal regions, a 20% increase in the total irregular electrical activity of the small intestine, and a 22% increase in duration of the meal response in the duodenum and jejunum. Renal failure did not change xylose absorption, gastric emptying rate, and orocolonic transit time but decreased colonic transit time by 38%. The mean weight of feces was increased. These results indicate that moderate renal failure alters duodenojejunal motility and decreases colonic transit time.
6
Engedal, Thorbjørn S., Niels Hjort, Kristina D. Hougaard, et al. "Transit time homogenization in ischemic stroke – A novel biomarker of penumbral microvascular failure?" Journal of Cerebral Blood Flow & Metabolism 38, no. 11 (2017): 2006–20. http://dx.doi.org/10.1177/0271678x17721666.
Full textAbstract:
Cerebral ischemia causes widespread capillary no-flow in animal studies. The extent of microvascular impairment in human stroke, however, is unclear. We examined how acute intra-voxel transit time characteristics and subsequent recanalization affect tissue outcome on follow-up MRI in a historic cohort of 126 acute ischemic stroke patients. Based on perfusion-weighted MRI data, we characterized voxel-wise transit times in terms of their mean transit time (MTT), standard deviation (capillary transit time heterogeneity – CTH), and the CTH:MTT ratio (relative transit time heterogeneity), which is expected to remain constant during changes in perfusion pressure in a microvasculature consisting of passive, compliant vessels. To aid data interpretation, we also developed a computational model that relates graded microvascular failure to changes in these parameters. In perfusion–diffusion mismatch tissue, prolonged mean transit time (>5 seconds) and very low cerebral blood flow (≤6 mL/100 mL/min) was associated with high risk of infarction, largely independent of recanalization status. In the remaining mismatch region, low relative transit time heterogeneity predicted subsequent infarction if recanalization was not achieved. Our model suggested that transit time homogenization represents capillary no-flow. Consistent with this notion, low relative transit time heterogeneity values were associated with lower cerebral blood volume. We speculate that low RTH may represent a novel biomarker of penumbral microvascular failure.
7
Rouhanizadeh, Behzad, and Sharareh Kermanshachi. "Development of Strategies to Prevent Third Rail Insulator Failures in Transit Systems." Urban Rail Transit 7, no. 1 (2021): 58–70. http://dx.doi.org/10.1007/s40864-021-00142-x.
Full textAbstract:
AbstractFailures of third rail insulators, which often impose problems that affect the serviceability of transit systems, rarely have been investigated. This study examines various aspects of third rail systems, identifies causes of insulator failures, and develops and categorizes preventive strategies. To accomplish the goals, the existing literature was reviewed and analyzed to identify various characteristics of third rails and insulators. Then, five transit case studies were analyzed to determine the characteristics of third rails, identify the causes of insulator failures, and evaluate the preventive strategies adopted by transit agencies. The results revealed that local environmental conditions cause degradation of insulators, with dirt build-up being the biggest contributor to failure. Performing maintenance and inspections of insulators at predetermined intervals was also shown to be very effective for preventing failure. The preventive strategies were classified into three categories: regular inspections; preventive maintenance programs; and regulation and safety, with regular inspections being the most frequently adopted. Findings of this study will serve as an appropriate source of information for practitioners who work with third rail systems and will help them adopt effective strategies.
8
Xu, Xueguo, Chen Xu, and Wenxin Zhang. "Research on the Destruction Resistance of Giant Urban Rail Transit Network from the Perspective of Vulnerability." Sustainability 14, no. 12 (2022): 7210. http://dx.doi.org/10.3390/su14127210.
Full textAbstract:
Giant urban rail transit (GURT) systems have been formed in many metropolises and play a critical role in addressing serious traffic congestion. Unfortunately, as a dynamic and complex system, the vulnerability of GURT networks under various failure scenarios will be more prominent as the network expansion continues. Thus, it is imperative to explore the complex structural characteristics of the network and improve the ability to deal with the disturbance of emergencies. In this study, the destruction resistance of GURT networks with scale growth is illustrated from a vulnerability perspective. Specifically, taking Shanghai rail transit (SHRT) system as an example, the network topology model is constructed using the Space L method, and the network structure characteristics are analyzed based on the complex network theory. In addition, five attack strategies are developed to represent random and targeted attacks during the simulation of network failure, and two metrics are determined to evaluate the network vulnerability. Some meaningful results have been obtained: (i) The Shanghai rail transit planning network (SHRTPN) has increased the network efficiency by more than 10% over the Shanghai rail transit operating network (SHRTON) and has effectively enhanced the network destruction resistance. (ii) The SHRT network is a small-world network and shows significant vulnerability under the targeted attacks. The failure of only 3% high betweenness stations in SHRTON can lead to a 66.2% decrease in the network efficiency and a 75.8% decrease in the largest connected component (LCC) ratio. (iii) Attacking stations will cause more severe network failures than attacking edges, and it is necessary to focus on preventing catastrophic network failure caused by the critical station’s failure breaking the threshold. Finally, the strategies for improving the destruction resistance of GURT networks are proposed. The findings of this research can provide an essential reference for the rational planning, safety protection, and sustainable construction of GURT systems.
9
Rouhanizadeh, Behzad, and Sharareh Kermanshachi. "Third-Rail Insulator Failure Causes and Mitigating Practices: A Comparative Study of Multiple Case Studies in the U.S." Urban Rail Transit 6, no. 4 (2020): 205–17. http://dx.doi.org/10.1007/s40864-020-00134-3.
Full textAbstract:
AbstractRail transit systems are one of the most important and popular types of transit systems used daily in metropolitan areas all around the world. The third rail is one of the providers of traction power in electrified rail systems, but it faces several issues, such as insulator failures. The purpose of this study is to investigate the causes of insulator failures, which have not been comprehensively studied and presented in the literature. To accomplish this objective, eight transit systems with third rails were selected to (1) investigate the characteristics of third-rail systems, (2) determine the causes of insulator failures, (3) analyze the costs associated with insulator failures, and (4) determine mitigating practices to reduce the number and cost of insulator failures. After a thorough literature review, details of eight case studies were collected from different transit agencies, and their subject matter experts were asked to complete a survey and provide input. The results revealed that a build-up of dirt was the major cause of the 17 identified causes of insulator failures; carbon dust and dirt were identified as the most present particles in third-rail systems. It was noted that transit agencies often implement multiple mitigating practices such as cleaning the insulator, performing visual inspections, and conducting regular maintenance to reduce the number and cost of insulator failures. The findings of this study will help decision-makers for transit systems make timely decisions to prevent third-rail insulator failures and adopt appropriate practices that best fit their transit system.
10
Langner, C., J. Barnert, A. Majewicz, and M. Wienbeck. "Orocecal transit time is prolonged in patients with heart failure." Gastroenterology 114 (April 1998): A784. http://dx.doi.org/10.1016/s0016-5085(98)83203-4.
Full text
11
Li, Dekui, Yuru Hou, Shubo Du, and Fan Zhou. "Cascading Failure and Resilience of Urban Rail Transit Stations under Flood Conditions: A Case Study of Shanghai Metro." Water 16, no. 19 (2024): 2731. http://dx.doi.org/10.3390/w16192731.
Full textAbstract:
The increasing frequency of urban flooding, driven by global climate change, poses significant threats to the safety and resilience of urban rail transit systems. This study systematically examines the cascading failure processes and resilience of these networks under flood conditions, with a specific focus on the Shanghai Metro. A comprehensive resilience evaluation model was developed by integrating geographic information, static network characteristics, and dynamic passenger flow indicators. This study employs an improved Coupled Map Lattice (CML) model to simulate cascading failures by considering the coupling effects of station centrality, geographic elevation, and passenger flow dynamics. The results indicate that stations with higher degrees of centrality are more likely to trigger rapid cascading failures across the network. However, incorporating dynamic passenger flow and geographic elevation data helps mitigate these effects, emphasizing the need for multi-dimensional resilience strategies. The findings provide valuable insights for urban transit management, offering a scientific foundation for developing targeted disaster response strategies to enhance network resilience against floods. This study advances our understanding of the vulnerability of urban rail transit systems and offers practical guidance for improving disaster preparedness in urban transportation infrastructure.
12
Groom, Robert, Joan Tryzelaar, Richard Forest, et al. "Intra-operative quality assessment of coronary artery bypass grafts." Perfusion 16, no. 6 (2001): 511–18. http://dx.doi.org/10.1177/026765910101600611.
Full textAbstract:
Early coronary artery bypass graft (CABG) failure is a troubling complication that may result in a wide range of problems, including refractory angina, myocardial infarction, low cardiac output, arrhythmia, and fatal heart failure. Early graft failures are related to poor quality and size of the distal native vascular bed, coagulation abnormalities, or technical problems involving the graft conduits and anastomoses. Unfortunately, graft failure is difficult to detect during surgery by visual assessment, palpation, or conventional monitoring. We evaluated the accuracy and utility of a transit-time, ultrasonic flow measurement system for measurement of CABGs. There were no differences between transit-time measurements and volumetric-time collected samples in an in vitro circuit over a range of flows from 10 to 100 ml/min (Bland and Altman Plot, 1.96 SD). Two hundred and ninety-eight CABGs were examined in 125 patients. Graft flow rate was proportional to the target vessel diameter. Nine technical errors were detected and corrected. Flow waveform morphology provided valuable information related to the quality of the anastamosis, which led to the immediate correction of technical problems at the time of surgery.
13
Rahimi, Ehsan, Ali Shamshiripour, Ramin Shabanpour, Abolfazl (Kouros) Mohammadian, and Joshua Auld. "Analysis of Transit Users’ Response Behavior in Case of Unplanned Service Disruptions." Transportation Research Record: Journal of the Transportation Research Board 2674, no. 3 (2020): 258–71. http://dx.doi.org/10.1177/0361198120911921.
Full textAbstract:
Public transit disruption is becoming more common across different transit services, and can have a destructive influence on the resiliency of the transportation system. Even though transit agencies have various strategies to mitigate the probability of failure in the transit system by conducting preventative actions, some disruptions cannot be avoided because of their either unpredictable or uncontrollable nature. Utilizing recently collected data of transit users in the Chicago Metropolitan Area, the current study aims to analyze how transit users respond to an unplanned service disruption and disclose the factors that affect their behavior. In this study, a random parameter multinomial logit model is employed to consider heterogeneity across observations as well as panel effects. The results of the analysis reveal that a wide range of factors including socio-demographic attributes, personal attitudes, trip-related information, and built environment are significant in passengers’ behavior in case of unplanned transit disruptions. Moreover, the effect of service recovery time on passengers is not the same among all types of disrupted services; rail users are more sensitive to the recovery time as compared with bus users. The findings of this study provide insights for transportation authorities to improve the transit service quality in relation to user satisfaction and transportation resilience. These insights help transit agencies to implement effective recovery strategies.
14
Akridge, Hunter, Alice Xiaodi Tang, Nikolas Martelaro, and Sarah E. Fox. "Punctuated and Prolonged: A Workers' Inquiry into Infrastructural Failures in Bus Transit." Proceedings of the ACM on Human-Computer Interaction 9, no. 2 (2025): 1–25. https://doi.org/10.1145/3710914.
Full textAbstract:
In North America, bus operators are essential but undervalued public servants — the ''human infrastructure'' of public transit. Transit workers face a range of largely invisible health and safety issues that have worsened in recent years. As more attention is directed toward new technologies being commercialized in the sector these operational challenges remain largely unaddressed. Our paper contributes to a turn ''back to labor'' and describes issues bus operators face on the job. Through a diary study of bus operators' working conditions we detail how punctuated moments of workplace violence, inhumane scheduling, and unsafe operational conditions become prolonged infrastructural failure. We outline how CSCW researchers and practitioners can contribute to the design of transit systems that enhance worker dignity and contribute to ongoing efforts to address urgent health and safety concerns.
15
Alirezaei, Toktam, and Zahra Ansari Aval. "Rescue thrombolysis partial failure in massive PE complicated with in-transit thrombus." International Medical Case Reports Journal Volume 12 (January 2019): 9–14. http://dx.doi.org/10.2147/imcrj.s189944.
Full text
16
Ye, Qian, and Hyun Kim. "Partial Node Failure in Shortest Path Network Problems." Sustainability 11, no. 22 (2019): 6275. http://dx.doi.org/10.3390/su11226275.
Full textAbstract:
This paper investigates the impact of partial node failure from the perspective of shortest path network problems. We propose a network model that we call shortest path network problems for partial node failure, designed to examine the influence of partial node failures in a flow-based network using a set of indicators. The concept of partial node failure was applied to a special type of hub station, a mandatory transfer in subway or railway systems where multiple lines are arranged for the transfer of passengers. Numerical experiments were carried out on the Washington Metropolitan Area Transit Authority network (WMATA). The results or analysis detail how changes in flow distribution in the network were measured when a station partially failed, as well as ways of identifying heavily impacted stations with respect to different indicators. Various partial node failure scenarios were simulated for origin–destination (OD) flows by days, providing comprehensive information with which to evaluate plans for partial node failures, such as those related to scheduling maintenance, along with insights with which to make contingent plans for potential closure of stations. A major finding emphasizes that the rankings of station criticality are highly sensitive to the different OD flows by days when partial node failures are assumed in network modeling.
17
Fu, Bai-Bai, Lin Zhang, Shu-Bin Li, and Yun-Xuan Li. "Survivability of public transit network based on network structure entropy." International Journal of Modern Physics C 26, no. 09 (2015): 1550104. http://dx.doi.org/10.1142/s0129183115501041.
Full textAbstract:
In this work, we have collected 195 bus routes and 1433 bus stations of Jinan city as sample date to build up the public transit geospatial network model by applying space L method, until May 2014. Then, by analyzing the topological properties of public transit geospatial network model, which include degree and degree distribution, average shortest path length, clustering coefficient and betweenness, we get the conclusion that public transit network is a typical complex network with scale-free and small-world characteristics. Furthermore, in order to analyze the survivability of public transit network, we define new network structure entropy based on betweenness importance, and prove its correctness by giving that the new network structure entropy has the same statistical characteristics with network efficiency. Finally, the "inflexion zone" is discovered, which can be taken as the momentous indicator to determine the public transit network failure.
18
An, Hyok, Yoonjong Na, Heejo Lee, and Adrian Perrig. "Resilience Evaluation of Multi-Path Routing against Network Attacks and Failures." Electronics 10, no. 11 (2021): 1240. http://dx.doi.org/10.3390/electronics10111240.
Full textAbstract:
The current state of security and availability of the Internet is far from being commensurate with its importance. The number and strength of DDoS attacks conducted at the network layer have been steadily increasing. However, the single path (SP) routing used in today’s Internet lacks a mitigation scheme to rapidly recover from network attacks or link failure. In case of a link failure occurs, it can take several minutes until failover. In contrast, multi-path routing can take advantage of multiple alternative paths and rapidly switch to another working path. According to the level of available path control, we classfy the multi-path routing into two types, first-hop multi-path (FMP) and multi-hop multi-path (MMP) routing. Although FMP routing supported by networks, such as SD-WAN, shows marginal improvements over the current SP routing of the Internet, MMP routing supported by a global Internet architecture provides strong improvement under network attacks and link failure. MMP routing enables changing to alternate paths to mitigate the network problem in other hops, which cannot be controlled by FMP routing. To show this comparison with practical outcome, we evaluate network performance in terms of latency and loss rate to show that MMP routing can mitigate Internet hazards and provide high availability on global networks by 18 participating ASes in six countries. Our evaluation of global networks shows that, if network attacks or failures occur in other autonomous systems (ASes) that FMP routing cannot avoid, it is feasible to deal with such problems by switching to alternative paths by using MMP routing. When the global evaluation is under a transit-link DDoS attack, the loss rates of FMP that pass the transit-link are affected significantly by a transit-link DDoS attack, but the other alternative MMP paths show stable status under the DDoS attack with proper operation.
19
Sun, Baofeng, Jiaojiao Liu, Junyi Hao, Xiuxiu Shen, Xinhua Mao, and Xianmin Song. "Maintenance Decision-Making of an Urban Rail Transit System in a Regionalized Network-Wide Perspective." Sustainability 12, no. 22 (2020): 9734. http://dx.doi.org/10.3390/su12229734.
Full textAbstract:
The networked operation of Urban Rail Transit (URT) brings the new challenge of network-wide maintenance. This research focuses on the URT Network-Wide Maintenance Decision-Making Problem (URT-NMDP), including regionalized maintenance network design and maintenance resource allocation. In this work, we proposed a bi-objective integer programming model that integrates the characteristics of set coverage and P-median models, resulting in the regionalized maintenance network design model. Some critical factors are considered in the model, such as the importance of node, the maximum failure response time, and maintenance guarantee rules. We designed a NSGA-II based algorithm to solve the model. Moreover, due to the uncertainty of failures in the URT network, we developed the method of allocating maintenance resources based on Monte Carlo simulation to strengthen the reliability of the regionalized maintenance network. With the model and algorithm presented in this work, we obtained Pareto optimal solutions of URT-NMDP, i.e., URT network-wide maintenance planning schemes, which include the number and location of maintenance points, the allocation of demand points, and the amount of maintenance units. Finally, a real-world case is studied to evaluate the operating performance of these schemes for verifying the method in our paper. The results of the case study demonstrate that the reasonable and tested-in-practice maximum failure response time is the precondition for the efficient URT maintenance network. The maintenance scheme considered the weighted importance of node shows the optimal performance, with the shortest overall maintenance path and the minimum average failure response time and investment cost on maintenance resources.
20
Ranjbari, Andisheh, Afshin Shariat Mohaymany, and S. M. Mahdi Amiripour. "Transit Network Design: The Necessity of Elastic Demand Consideration." Applied Mechanics and Materials 97-98 (September 2011): 1117–22. http://dx.doi.org/10.4028/www.scientific.net/amm.97-98.1117.
Full textAbstract:
Transit network design as the first and critical phase of public transportation planning is extremely sensitive to transit demand. An important characteristic of transit demand is elasticity or service-dependency, which means that any change in the service offered by the system is followed by a change in transit demand. Due to the complexity of transit network design problem (TNDP) researchers have usually assumed transit demand to be fixed rather than elastic; while ignoring this issue may result in inefficiency of system, dissatisfaction of users, and system failure, since the predicted amount of passengers would not use the transit system. This paper aims to demonstrate the necessity of elastic demand consideration in transit network design, and proposes a solution framework, which is composed of a preparation stage and an iterative procedure. A case study example is presented subsequently, to show the use of this solution method and further illustrates the necessity of considering this issue. Three cases of truly predicted demand (considering elastic demand), overestimated and underestimated demands (in the absence of elastic demand consideration) are defined, and the performance measures of these cases are compared to those in the base mode. The results show that elastic demand consideration leads to the optimal network, in which the system efficiently matches between supply and demand.
21
Huang, Ailing, H. Michael Zhang, Wei Guan, Yang Yang, and Gaoqin Zong. "Cascading Failures in Weighted Complex Networks of Transit Systems Based on Coupled Map Lattices." Mathematical Problems in Engineering 2015 (2015): 1–16. http://dx.doi.org/10.1155/2015/940795.
Full textAbstract:
Study on the vulnerability and robustness of urban public transit networks (PTNs) has great implications for PTNs planning and emergency management, particularly considering passengers’ dynamic behaviors. We made a complex weighted network analysis based on passenger flow for Beijing’s bus stop network and multimodal transit network coupled with bus and urban rail systems. The analysis shows that there are small-world or scale-free properties in these two networks, which make them display different robustness under link or node failures. With consideration of the dynamic flow redistribution, we propose a model based on coupled map lattices to analyze the cascading failures of these two weighted networks. We find that the dynamic flow redistribution can significantly improve the tolerance of small-world or scale-free PTN against random faults. Because of the coupling of bus and rail systems, the multimodal network with scale-free topology and flow distribution structures displays an increasing tolerance even against intentional attack; however, its cascade is also much more intense once the failure is triggered. We find some thresholds of topological and flow coupling strength in the spreading process, which can be exploited to develop strategies to control cascade failures.
22
He, Yaqin, Md Tawhidur Rahman, Michelle Akin, Yinhai Wang, Kakan Dey, and Xianming Shi. "Connected Vehicle Technology for Improved Multimodal Winter Travel: Agency Perspective and a Conceptual Exploration." Sustainability 12, no. 12 (2020): 5071. http://dx.doi.org/10.3390/su12125071.
Full textAbstract:
Accurate and real-time traffic and road weather information acquired using connected vehicle (CV) technologies can help commuters perform safe and reliable trips. A nationwide survey of transit operation managers/supervisors was conducted to assess the suitability for CV transit applications in improving the safety and mobility during winter weather. Almost all respondents expressed positive attitudes towards the potential of CV applications in improving winter transit travel and voiced their concerns over the safety consequences of CV equipment failure, potential of increased driver distraction, and reliability of system performance in poor weather. A concept of operations of CV applications for multimodal winter travel was developed. In the conceptual framework, route-specific road weather and traffic flow data will be used by the transit managers/supervisors to obtain real-time operational status, forecast operational routes and schedules, and assess operational performance. Subsequently, multimodal commuters can receive the road-weather and traffic-flow information as well as transit routes and schedule information.
23
Fireene, R., J. A. Correia, K. A. McKusick, H. W. Strauss, and W. Hereford. "185 FREQUENCY DISTRIBUTION OF PULMONARY VASCULAR TRANSIT TIMES IN ACUTE RESPIRATORY FAILURE." Investigative Radiology 21, no. 9 (1986): S47. http://dx.doi.org/10.1097/00004424-198609000-00203.
Full text
24
Oyan, C. "Structural strength analysis of the bogie frame in Taipei rapid transit systems." Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit 212, no. 3 (1998): 253–62. http://dx.doi.org/10.1243/0954409981530841.
Full textAbstract:
The importance of bogie fatigue in railway rolling stock has been recognized as a contributing factor in structural failure. A bogie frame designed for Taipei rapid transit systems is analysed in order to confirm the technical strength requirements for static and dynamic loadings. A numerical finite element analysis is utilized in view of the complex geometry, and detailed plots are also presented in this report to give a complete understanding of the behaviour of the bogie frame. The von Mises stresses are adopted as equivalent stresses in the static strength calculation while the principal stresses are adopted in fatigue strength evaluation. Material yield stress and modified Goodman diagrams showing the permissible stress ranges are used as failure criteria respectively for static and dynamic loadings. It is demonstrated that the static strength and fatigue strength of the bogie frame satisfy the strength requirements specified by Taipei rapid transit systems.
25
Xiaoliang, Zhang, and Jia Limin. "Discussion on Optimization of Public Transportation Network Setting considering Three-State Reliability." Journal of Advanced Transportation 2021 (July 24, 2021): 1–7. http://dx.doi.org/10.1155/2021/6940263.
Full textAbstract:
In order to be environment-friendly, relieve traffic congestion, reduce pollution, and be green and sustainable, the optimization and development of public transportation, as the subject of people's long-term research, has always been shining. With the emergence of shared transportation, public transportation systems face more challenges. In order to better connect with bike-sharing, car-sharing, and other modes of transportation, public transportation will carry out important reforms, among which the optimization of line network is one of the most important tasks. The traditional bus route design is mainly based on the “four-stage” method model, which is mainly based on the investigation and analysis of the existing traffic system and land use. Through the work flow of “evaluation, calibration, and verification,” the network balance optimization model is used to get the bus travel allocation prediction model. In this paper, the optimization problem of public transit network is studied from the point of view of the reliability of public transit network. It is proposed that public transit network can be abstracted into series-parallel system and parallel-series system model from the three states of normal, short-circuit failure, and open-circuit failure and is analyzed and discussed through the hypothesis experiment. The research of this paper will provide a new perspective for the optimization of public transit network, complement the traditional methods, and support the optimization and reliability improvement of urban public transit network. More reliable bus networks and other modes of transportation, such as walking, bike-sharing, and rail, will become more suitable for people to get around.
26
Hu, Junhong, Mingshu Yang, and Yunzhu Zhen. "A Review of Resilience Assessment and Recovery Strategies of Urban Rail Transit Networks." Sustainability 16, no. 15 (2024): 6390. http://dx.doi.org/10.3390/su16156390.
Full textAbstract:
Rail transit is an important means of ensuring the sustainable development of urban transportation, but disturbance events caused by natural disasters, human factors, and other influences can lead to disruptions in rail transit operations. To cope with the impact of disturbance events on urban rail transit networks, and to explore the changes in rail transit network performance and recovery strategies under the influence of disturbance events from a resilience perspective, this paper overviews the existing research on resilience assessment and recovery strategies for urban rail transit networks. Firstly, the characteristics of the urban rail transit network and the model construction method are analyzed. Secondly, on the basis of combing the connotation development of system resilience, urban rail transit network resilience is defined, while the existing resilience metrics and assessment indexes are classified and summarized. Finally, the failure scenarios and recovery strategies of urban rail transportation network are deeply studied and discussed. The research results show that urban rail transit network resilience has been widely concerned by scholars, and certain results have been achieved in three aspects of resilience connotation, resilience assessment and recovery strategy. Nevertheless, further research is needed on these aspects. We propose future research directions that involve exploring modeling methods aligned with actual network topologies, developing unified indexes for resilience assessment and focusing on resilience assessment and recovery strategies under uncertain disturbance events. The research results can provide an important reference for the resilient operation and sustainable construction of urban rail transit.
27
Park, Keunhyun, Reid Ewing, Brenda Case Scheer, and Shabnam Sifat Ara Khan. "Travel Behavior in TODs vs. Non-TODs: Using Cluster Analysis and Propensity Score Matching." Transportation Research Record: Journal of the Transportation Research Board 2672, no. 6 (2018): 31–39. http://dx.doi.org/10.1177/0361198118774159.
Full textAbstract:
As a compact, mixed-use, and walkable district near a high-quality transit station, transit-oriented development (TOD) has arisen as a sustainable form of urbanism to minimize automobile dependency and maximize ridership. Existing travel behavior studies in the context of TOD, however, are limited in terms of small sample size, lack of consistency in TOD classification, and failure to control for residential self-selection. This study examines various travel outcomes—vehicle miles traveled (VMT), auto trips, transit trips, and walk trips—in different types of station areas in eight U.S. metropolitan areas using cluster analysis and propensity score matching. Using cluster analysis with three built environment factors—activity density, land use diversity, and street network design (i.e., D variables)—this study classifies existing 549 station areas as TOD, transit-adjacent development (TAD), and Hybrid types. After controlling for residential self-selection, the result shows that a TOD motivates its residents to walk more and take transit more while driving less. The significant difference between TOD and TAD in both VMT and the number of automobile trips means that TOD makes the personal vehicle trips shorter (39% reduction) and fewer (35% reduction). Travel behaviors in the Hybrid type are also examined for the potential outcomes of gradual and practical changes.
28
Li, James. "Reliability Calculation for Dormant k-out-of-n Systems with Periodic Maintenance." International Journal of Mathematical, Engineering and Management Sciences 1, no. 2 (2016): 68–76. http://dx.doi.org/10.33889/ijmems.2016.1.2-008.
Full textAbstract:
In this paper, a dormant k-out-of-n systems redundancy calculation will be introduced. Dormant failure is a failure that cannot be detected when it occurs because of the nature of the failure characteristic. Therefore, a dormant failure becomes the blind point to the design for reliability and maintainability because of its inability to be detected. The most popular approach in detecting a dormant failure is to carry out a scheduled periodic inspection, test or maintenance activity. The scheduled periodic maintenance is applied to prevent and reduce the unexpected dormant failures that could lead to safety consequences, or costly corrective maintenance. This paper will introduce a methodology on how to calculate the reliability parameter such as Mean Time Between Failure (MTBF) for the dormant k-out-of-n redundant systems. The mathematical relationship between the effective MTBF and the scheduled periodic inspection/maintenance interval is also elaborated. Case studies are adopted to illustrate how to apply the developed reliability calculation methodology in the mass transit train reliability and safety design.
29
Sun, Ranran, Guangyu Zhu, Bing Liu, Xiaolu Li, Yiyuan Yang, and Jingxuan Zhang. "Vulnerability Analysis of Urban Rail Transit Network considering Cascading Failure Evolution." Journal of Advanced Transportation 2022 (April 11, 2022): 1–16. http://dx.doi.org/10.1155/2022/2069112.
Full textAbstract:
Vulnerability analysis is the premise of operational risk management and control for the large-scale and complex urban rail transit network (URTN) under the operation interruption of important stations. The temporary operation interruption of one station in an emergency may lead to the cascading failure and the paralysis of the whole URTN due to the load of other stations exceeding the limited capacity. The priority of important stations is proposed by combining its location and function in URTN. In addition, focusing on the analysis of the travel behaviour of passengers and the synergy of public transport networks, a novel cascading failure evolution model is established to simulate the cascading failure process of URTN under different attack scenarios. The vulnerability indicators are constructed to dynamically evaluate the vulnerability of URTN considering cascading failure evolution, which are different from the traditional vulnerability indicators based on complex network theory. Taking the Beijing urban rail transit network as an example, the dynamic simulation results show that the cascading failure of URTN is closely related to the temporal-spatial distribution of passenger flows and malicious attacks are more destructive than random attacks. Compared with the important stations with the largest betweenness or degree, the interrupted stations with largest intensity have a greater impact on the operational stability of URTN. Moreover, increasing the capacity coefficient of the station can reduce the vulnerability of URTN.
30
Wang, Yuhao, Jie Liu, and Zhouyu Li. "The Resilience of an Urban Rail Transit Network: An Evaluation Approach Based on a Weighted Coupled Map Lattice Model." Mathematics 13, no. 4 (2025): 608. https://doi.org/10.3390/math13040608.
Full textAbstract:
Modeling cascading failure in an urban rail transit network (URTN) is essential for evaluating the impact of interruptions and network resilience. Here, a weighted coupled map lattice (CML) model is proposed. This model combines structural network coupling and passenger flow coupling to analyze the cascading failure process triggered by a station failure. Four network performance indicators are developed: network efficiency and subgraph connectivity from the network structure perspective, and OD connectivity and the reciprocal of average transfers from the network service perspective. The resilience of a URTN is measured based on the network performance indicators during station failures. Application of the model to the Wuhan URTN showed that station failure with high numbers of boarding and alighting passengers caused the highest decline in network resilience. The network’s structural resilience was stronger than its service resilience. The relationship between the percentage of failed stations and network performance indicated a significant threshold effect at a 5% failure percentage. Specifically, network performance decreased rapidly when the percentage of failed stations was below 5% and more gradually when it exceeded this threshold. Moreover, network performance exhibited high sensitivity to increases in external perturbation intensity when the failure station percentage was below 5%, but this sensitivity diminished significantly once the percentage surpassed 5%.
31
Jin, Kun, Wei Wang, Xinran Li, Siyuan Chen, Shaoyang Qin, and Xuedong Hua. "Cascading failure in urban rail transit network considering demand variation and time delay." Physica A: Statistical Mechanics and its Applications 630 (November 2023): 129290. http://dx.doi.org/10.1016/j.physa.2023.129290.
Full text
32
Dr., KASHIF RATHORE, and ALI KASHIF. "Evaluation of Lahore Bus Rapid Transit System." International Journal of Management Sciences and Business Research 4, no. 10 (2015): 138–48. https://doi.org/10.5281/zenodo.3462988.
Full textAbstract:
This study evaluates Lahore bus rapid transit system according to BRT standard 2014. This study concludes that deviation from proposed transport policies is one of the factors that lead towards the failure of urban transport system in Lahore. Government did not pay proper attention to the recommendations proposed in different transport studies conducted by JICA and other transport institutions. The Lahore BRT has failed to receive gold, silver or bronze standard as it only achieved “Basic BRT” status. Lahore BRT is experiencing swear maintenance and operational issues that may lead towards the failure of Lahore BRT system in terms of passengers discomfort and reliability of the system may get affected in future.
33
Huang, Cong, and Ying Huang. "Research and design of data communication subsystem of urban rail transit CBTC system." International Journal of System Assurance Engineering and Management 12, no. 4 (2021): 629–39. http://dx.doi.org/10.1007/s13198-021-01055-5.
Full textAbstract:
AbstractWith the intensive development of urban rail transit in China, urban rail transit has increasingly become the preferred mode of transportation for citizens due to its convenience and speed. The design and construction of an efficient and highly reliable urban rail transit system has become an urgent requirement for urban rail transit construction. This article mainly introduces the research and design of the data communication subsystem of the urban rail transit CBTC system, and intends to provide some ideas and directions for studying the data communication subsystem of the urban rail transit CBTC system. This article uses a variety of methods, such as consulting literature and information research on trademark system suppliers. The development status of CBTC system and data communication subsystem is analyzed, and the importance of data communication subsystem and the necessity of the entire CBTC system are analyzed. The experimental results of this article show that in the design, development and application engineering of the CBTC system, the DCS subsystem accounts for 55%, the system is complex, and the environment is changeable, occupying an important position. When the DCS has a problem, it may cause drive failure, affect normal functions, cause greater losses, and even cause huge safety accidents. Therefore, the reasonable, reliable and safe design of the DCS subsystem is of great significance.
34
Janssen, B., J. Debets, P. Leenders, and J. Smits. "Chronic measurement of cardiac output in conscious mice." American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 282, no. 3 (2002): R928—R935. http://dx.doi.org/10.1152/ajpregu.00406.2001.
Full textAbstract:
We describe the feasibility of chronic measurement of cardiac output (CO) in conscious mice. With the use of gas anesthesia, mice >30 g body wt were instrumented either with transit-time flow probes or electromagnetic probes placed on the ascending aorta. Ascending aortic flow values were recorded 6–16 days after surgery when probes had fully grown in. In the first set of experiments, while mice were under ketamine-xylazine anesthesia, estimates of stroke volume (SV) obtained by the transit-time technique were compared with those simultaneously obtained by echocardiography. Transit-time values of SV were similar to those obtained by echocardiography. The average difference ± SD between the methods was 2 ± 7 μl. In the second set of studies, transit-time values of CO were compared with those obtained by the electromagnetic flow probes. In conscious resting conditions, estimates (±SD) of cardiac index (CI) obtained by the transit-time and electromagnetic flow probes were 484 ± 119 and 531 ± 103 ml · min−1 · kg body wt−1, respectively. Transit-time flow probes were also implanted in mice with a myocardial infarction (MI) induced by ligation of a coronary artery 3 wk before probe implantation. In these MI mice ( n = 7), average (±SD) resting and stimulated (by volume loading) values of CO were significantly lower than in noninfarcted mice ( n = 15) (resting CO 16 ± 3 vs. 20 ± 4 ml/min; stimulated CO 20 ± 5 vs. 26 ± 6 ml/min). Finally, using transfer function analysis, we found that, in resting conditions for both intact and MI mice, spontaneous variations in CO (>0.1 Hz) were mainly due to those occurring in SV rather than in heart rate. These data indicate that CO can be measured chronically and reliably in conscious mice, also in conditions of heart failure, and that variations in preload are an important determinant of CO in this species.
35
Alsahafi, Majid, Paula Cramer, Nazira Chatur, and Fergal Donnellan. "The Effect of Prucalopride on Small Bowel Transit Time in Hospitalized Patients Undergoing Capsule Endoscopy." Canadian Journal of Gastroenterology and Hepatology 2017 (2017): 1–7. http://dx.doi.org/10.1155/2017/2696947.
Full textAbstract:
Background. The inpatient status is a well-known risk factor for incomplete video capsule endoscopy (VCE) examinations due to prolonged transit time. We aimed to evaluate the effect of prucalopride on small bowel transit time for hospitalized patients undergoing VCE. Methods. We included all hospitalized patients who underwent VCE at a tertiary academic center from October 2011 through September 2016. A single 2 mg dose of prucalopride was given exclusively for all patients who underwent VCE between March 2014 and December 2015. VCE studies were excluded if the capsule was retained or endoscopically placed, if other prokinetic agents were given, in cases with technical failure, or if patients had prior gastric or small bowel resection. Results. 442 VCE were identified, of which 68 were performed in hospitalized patients. 54 inpatients were included, of which 29 consecutive patients received prucalopride. The prucalopride group had a significantly shorter small bowel transit time compared to the control group (92 versus 275.5, p<0.001). There was a trend for a higher completion rate in the prucalopride group (93.1% versus 76%, p=0.12). Conclusions. Our results suggest that the administration of prucalopride prior to VCE is a simple and effective intervention to decrease small bowel transit time.
36
CENEVIVA, REGINALDO. "Duodenum inclusion in alimentary transit for preventing or correcting nutritional deficiencies resulting from Roux-en-y gastric bypass in obesity treatment." Revista do Colégio Brasileiro de Cirurgiões 43, no. 2 (2016): 136–38. http://dx.doi.org/10.1590/0100-69912016002011.
Full textAbstract:
ABSTRACT Nutritional and metabolic complications can develop after Roux-en-Y gastric bypass (RYGB) when there is an exaggerated response to the anatomical and functional changes or when there is inadequate nutritional supplementation. Severe malnutrition is rare, but deficiencies of vitamin B12, iron, calcium and thiamin, metabolic bone disease and gallstones are common after RYGB. Shortage of vitamin B12, iron, calcium and also cholelithiasis are caused at least partially by excluding the duodenum and proximal jejunum from food transit. We designed a new procedure, with the maintenance of the duodenum and proximal jejunum in the gastrointestinal transit through interposition of jejunal loop, as a primary operation to prevent such deficiencies or as corrective surgery for severe malnutrition after RYGB with failure in responding to conservative treatment.
37
Chervinska, Olha. "Success as Failure, Failure as Success." Pitannâ lìteraturoznavstva, no. 107 (June 30, 2023): 9–15. http://dx.doi.org/10.31861/pytlit2023.107.009.
Full textAbstract:
The article under studies outlines the parameters of the paradigm “success” in relation to the concept of “category”. Hereby, success is interpreted as an ontological phenomenon, as a creative objective of any activity. The metaphysical parameters of success are outlined through a number of additional concepts-markers: avant-garde (innovation), historical time, goal, conjuncture, context, method, style, leap, boundary, summit, victory, authority, even a lucky coincidence. All of them require compliance with their own criteria. Success can come to authors years and even centuries after their death (Homer, Dante Alighieri, Shakespeare, Friedrich Hölderlin, Byron, Emily Dickinson, Vasyl Stus). The same happens to certain texts that may even be alienated from the author (for example, Scheherazade’s fairy tales, chivalric novels, Ukrainian dumas, which are currently successfully exploited by the genre of fantasy). The transit of such successful themes and texts was recorded by A. Volkov’s school of TPI (last quarter of the previous century). Its representatives agreed that imitation is mainly produced by the success of the original source. Referring to the canonical circle of literary names (for example, those identified by H. Bloom), we observe the lack of argumentation for common criteria for evaluating each of these writers. The most interesting things can happen to an artist in the future, in the shadows, because success is mostly a turning point, not the end of his or her life trajectory. Success as a specific emotional cleansing of the soul, in fact, its devastation, can put a tragic end to a biography. Therefore, when taken together, success and failure appear as an important dichotomous compound, the most essential intentional levers of subjective self-determination. The author’s interpretation of the paradigm of “success” is regarded in this article on the example R.-M. Rilke’s poetic text “The Beholder”.
38
Ge, Yifan, Lei Wu, Yifan Shen, and Jiawei Shi. "Research on the quality evaluation method of rail transit vehicles maintenance based on the life cycle." Journal of Physics: Conference Series 2369, no. 1 (2022): 012093. http://dx.doi.org/10.1088/1742-6596/2369/1/012093.
Full textAbstract:
In order to adapt to the current life cycle management mode of rail transit, this paper proposes a quality evaluation model based on vehicle life cycle maintenance. This model has three parts, which are objective evaluation, subjective evaluation and operational impact. The statistical process control method (SPC) is used in the objective evaluation. The subjective evaluation uses fuzzy algorithms to calculate the factors and weights that affect the maintenance quality, and then weights the actual number of failures to obtain the line deductions. Operation impact evaluation takes the main line failure as the analysis object, and combines the time, location and impact of the failure to obtain the line’s operational quality score. Then calculate the score of these three parts, the final line maintenance quality score. This evaluation system can more truly reflect the maintenance quality, and it has been applied in some pilot lines.
39
Sun, Jin Shan, Ming Chen, and Qing Hui Jiang. "Numerical Simulation of the Forming and Failure Process of Soil Arching Between Anti-slide Piles." Advanced Materials Research 261-263 (May 2011): 1614–18. http://dx.doi.org/10.4028/www.scientific.net/amr.261-263.1614.
Full textAbstract:
The mechanism of soil arching effect is important for anti-slide pile design. With the 2D particle flow method (PFC2D), the forming and failure process of the soil arching between anti-slide piles are simulated. The results show that the forming mechanism of soil arching mainly depended on stress transit process of micro soil granule. In the anti-slide pile numerical models (PFC2D), the contact stress transit trace lines present the tree crown shape, which centered about the anti-slide pile. The load from far field is transited to the front and side part of piles through the compress soil. When the soil between anti-slide piles collapses, the failure surface presented the arching shape. The cross-section and spacing of anti-slide piles affect the soil arching shape strongly. With the same pile spacing and soil parameters, the ultimate bearing capacity of rectangular cross-section pile is larger than the circle cross-section pile.
40
Wang, Jinle, Bing Yang, Honglei Tian, Wenbin Wang, and Xu Sang. "Optimization Design and Mechanical Performance Study of Carbon Fiber-Reinforced Composite Load-Carrying Structures for Subway Driver Cabin." Materials 18, no. 11 (2025): 2524. https://doi.org/10.3390/ma18112524.
Full textAbstract:
This study systematically investigates the optimization design and mechanical performance of carbon fiber-reinforced polymer (CFRP) load-carrying structures for subway driver cabins to meet the lightweight demands of rail transit. Through experimental testing and micromechanical modeling, the mechanical properties of CFRP and foam core materials were characterized, with predicted elastic constants exhibiting an error of ≤5% compared with experimental data. A shape optimization framework integrating mesh morphing and genetic algorithms achieved a 22% mass reduction while preserving structural performance and maintaining load-carrying requirements. Additionally, a stepwise optimization strategy combining free-size, sizing, and stacking sequence optimization was developed to enhance layup efficiency. The final design reduced the total mass by 29.1% compared with the original model, with all failure factors remaining below critical thresholds across three loading cases. The increased failure factor confirmed that the optimized structure effectively exploited the material’s potential while eliminating redundancy. These findings provide valuable theoretical and technical insights into lightweight CFRP applications in rail transit, demonstrating significant improvements in structural efficiency, safety, and manufacturability.
41
Kwong, Ivan, Mehdi Nourinejad, and Amer Shalaby. "Existing Problems of Transit Signal Priority on Streetcar Routes." Transportation Research Record: Journal of the Transportation Research Board 2674, no. 10 (2020): 861–73. http://dx.doi.org/10.1177/0361198120937310.
Full textAbstract:
Transit signal priority (TSP) is a traffic control strategy that gives priority to transit vehicles by adjusting intersection signals in real time. The technology is implemented in many major cities and has proved to benefit transit routes in reducing the overall passenger travel time. Unfortunately, there are several problems with TSP that are commonly ignored. These problems are predominantly operational, such as misjudgment of the arrival time at the intersection and insensitivity to the TSP activation time. It is worsened with streetcars, which have shorter headways and thus are more prone to bunching delays. In this paper, five delay problems that streetcars experience are identified. Data are collected from a TSP-equipped intersection in the City of Toronto to provide a statistical analysis of the issues. It was found that 25.8% of times, TSP is inadequate at prioritizing public transit. From the problems raised, the most frequent one is the late arrival of a streetcar during a green interval, representing 72.5% of TSP issue cases. It was also found that TSP has a bias toward different failure cases, and favors early arrivals to the intersection. Several remedies for the defined issues are recommended. The suggestions include implementing green truncations, avoiding late TSP activation in each cycle, and introducing a prediction-based TSP system.
42
Mori, T., T. Sugiyama, I. Hosooka, M. Nakata, K. Okano, and Y. Satofuka. "SLOPE FAILURE RISK ASSESSMENT MODELING USING TOPOGRAPHIC DATA AND NUMERICAL CALCULATION OF SOIL CONSERVATION BY TREE ROOT SYSTEMS." ISPRS Annals of Photogrammetry, Remote Sensing and Spatial Information Sciences IV-2/W5 (May 29, 2019): 217–22. http://dx.doi.org/10.5194/isprs-annals-iv-2-w5-217-2019.
Full textAbstract:
<p><strong>Abstract.</strong> In Japan, the frequency of sudden heavy rain events has recently increased, causing slope failures that in turn increase rates of damage to transit infrastructure such as railways and roads. To reduce this damage, there is a need to identify locations near railroad tracks that are at risk of slope failure. Thus, an assessment that predicts whether or not damage will occur due to external forces such as heavy rains is required, rather than a simple relative risk assessment based on identifying locations similar to those damaged in previous events. In this study, we developed a method for time series stability assessment of slopes during heavy rains using digital topographic data. This method uses topographic data to estimate topsoil thickness, which contributes to stability, and soil strength, which is affected by the root systems of vegetation on slopes. Using differences in these parameters between tree species and forest type, we were able to calculate slope stability and simulate slope failure during rainfall. The simulations allowed us to evaluate locations along routes where previous failures occurred, and to identify at-risk locations that have not yet experienced slope failure. This approach will improve forest management based on risk assessments for intensifying heavy rains.</p>
43
Tong, Jin, and Wangda Xu. "CT Imaging Characteristics and Influence Factors of Renal Dialysis-Associated Peritoneal Injury." Journal of Healthcare Engineering 2021 (April 20, 2021): 1–10. http://dx.doi.org/10.1155/2021/5591124.
Full textAbstract:
Peritoneal dialysis (PD), as one of the main renal replacement modalities for end-stage renal disease, gets the advantages of better protection of residual renal function and better quality of survival. However, ultrafiltration failure after peritoneal injury is an important reason for patients to withdraw from PD treatment. Peritonitis is a major complication of peritoneal dialysis, which results in an accelerated process of peritoneal injury due to direct damage from acute inflammation and local release of cytokine TGF-β. In this paper, the application of ultrasound to examine the peritoneum revealed a positive correlation between peritoneal thickness and the development of peritonitis. The results of this study also further confirmed the effect of peritonitis on peritoneal thickening. A multifactorial regression analysis also revealed that peritonitis and its severity were independent risk factors for peritoneal thickening and omental structural abnormalities. This paper reported a correlation between mural peritoneal thickness and peritoneal transit function. In this study, patients with high peritoneal transit and high mean transit were found to be more prone to omental structural abnormalities than patients with low mean and low transit and a higher proportion of patients with mural peritoneal thickening, but this did not reach statistical significance, which may be related to the still small number of cases.
44
Herold, Ingeborg H. F., Salvatore Saporito, Massimo Mischi, et al. "Pulmonary transit time measurement by contrast-enhanced ultrasound in left ventricular dyssynchrony." Echo Research and Practice 3, no. 2 (2016): 35–43. http://dx.doi.org/10.1530/erp-16-0011.
Full textAbstract:
Background Pulmonary transit time (PTT) is an indirect measure of preload and left ventricular function, which can be estimated using the indicator dilution theory by contrast-enhanced ultrasound (CEUS). In this study, we first assessed the accuracy of PTT-CEUS by comparing it with dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI). Secondly, we tested the hypothesis that PTT-CEUS correlates with the severity of heart failure, assessed by MRI and N-terminal pro-B-type natriuretic peptide (NT-proBNP). Methods and results Twenty patients referred to our hospital for cardiac resynchronization therapy (CRT) were enrolled. DCE-MRI, CEUS, and NT-proBNP measurements were performed within an hour. Mean transit time (MTT) was obtained by estimating the time evolution of indicator concentration within regions of interest drawn in the right and left ventricles in video loops of DCE-MRI and CEUS. PTT was estimated as the difference of the left and right ventricular MTT. Normalized PTT (nPTT) was obtained by multiplication of PTT with the heart rate. Mean PTT-CEUS was 10.5±2.4s and PTT-DCE-MRI was 10.4±2.0s (P=0.88). The correlations of PTT and nPTT by CEUS and DCE-MRI were strong; r=0.75 (P=0.0001) and r=0.76 (P=0.0001), respectively. Bland–Altman analysis revealed a bias of 0.1s for PTT. nPTT-CEUS correlated moderately with left ventricle volumes. The correlations for PTT-CEUS and nPTT-CEUS were moderate to strong with NT-proBNP; r=0.54 (P=0.022) and r=0.68 (P=0.002), respectively. Conclusions (n)PTT-CEUS showed strong agreement with that by DCE-MRI. Given the good correlation with NT-proBNP level, (n)PTT-CEUS may provide a novel, clinically feasible measure to quantify the severity of heart failure. Clinical Trial Registry: NCT01735838
45
Yang, Yang, Ailing Huang, and Wei Guan. "Statistic properties and cascading failures in a coupled transit network consisting of bus and subway systems." International Journal of Modern Physics B 28, no. 30 (2014): 1450212. http://dx.doi.org/10.1142/s0217979214502129.
Full textAbstract:
A coupled network model consisting of bus and subway systems is proposed, and the statistic properties of the three networks: bus, subway and coupled networks of Beijing are studied with the theory of complex network. The result shows that the three networks have typical properties of small-world. We propose three parameters to depict the coupled network, they are: the coupled parameter β the influence parameter S and the node tolerance parameter γ. We use the binary influence model to simulate a feedback process and cascading failure in the coupled network and we obtain the conclusions: (1) The cascading size grows with β; (2) The cascading size grows with S, but it has a critical point; (3) The cascading size grows with the decrease of γ, when γ≤0.3, the cascading failure will extent to the whole network.
46
Fang, Hui, and Wei Zhang. "Optimization and Application of Communication Resource Allocation Algorithm for Urban Rail Transit Planning." Computational Intelligence and Neuroscience 2022 (August 25, 2022): 1–9. http://dx.doi.org/10.1155/2022/5608665.
Full textAbstract:
The construction and operation of China’s rail transit system have entered a high-speed development stage, and the rapid increase of train speed and mileage has brought greater challenges to the safety and reliability of the rail transit system. Network planning evaluation is the key to the early decision-making of urban rail transit project, which directly determines the success or failure of the whole project. How to scientifically and reasonably evaluate the urban rail transit information resource network planning has become a difficult problem for many urban planners to solve. Therefore, this paper studies the optimization of the communication resource allocation algorithm and the comprehensive evaluation of its application for urban rail transit planning. In this paper, based on CVNN structure, the network prototype is an extension of RVNN structure. In the abstract, its processing unit is composed of a pair of real-number processors that can realize certain operations. HNN is a fully connected recurrent neural network based on the idea of the energy function, which is helpful to understand the calculation mode of HNN, and the research shows that HNN can solve many combinatorial optimization problems. In addition, the combination of neural network and genetic algorithm with simulated annealing mechanism can also bring new directions for research. On the basis of experimental analysis, it can be concluded that in general, the error reduction rate of the optimization scheme designed in this paper can reach 58.6% on average. In practical application, the accuracy of the optimal bit error rate is 52.4%.
47
Najafi-Zangeneh, Saeed, Naser Shams Gharneh, Ali Arjomandi-Nezhad, and Erfan Hassannayebi. "A Hybrid Machine Learning and Optimization Model to Minimize the Total Cost of BRT Brake Components." Journal of Advanced Transportation 2021 (October 22, 2021): 1–11. http://dx.doi.org/10.1155/2021/5590780.
Full textAbstract:
Public transport is amongst critical infrastructures in modern cities, especially megacities, home to millions of people. The reliability of these systems is highly crucial for both citizens and service providers. If service providers overlook system reliability, a considerable amount of expenses will be wasted. Several factors such as vehicle failure, accident, lack of budget weather factors, and traffic congestion cause unreliability, among which vehicle failure plays a prominent role. The brake system is the most vulnerable and vital component of a public transportation bus. Brake reliability depends on driver’s expertise, component quality, passenger loading, line situation, etc. Driver’s expertise and components’ quality are the most important factors for brake system reliability. This study aims to implement a hybrid machine learning and optimization model to minimize the total investment and reliability-related costs in a bus rapid transit (BRT) system. A regression analysis method is proposed to capture the main attributes of a joint brake system, including the level of education, training, and drivers’ experience. The failure rate is modeled as a linear function of ETE and the quality of brake system subcomponents using a Lasso regression model. MILP optimization is then provided for optimizing the total expected costs for a bus rapid transit (BRT) system. Furthermore, a practical case is studied to investigate whether this optimization can reduce costs. The results confirm the efficiency of the hybrid optimization approach.
48
Kozlov, Boris N., Vasily V. Zatolokin, Andrew V. Mochula, et al. "Intraoperative Prediction of Coronary Graft Failure Based on Transit Time Flow Measurement." Diagnostics 14, no. 17 (2024): 1903. http://dx.doi.org/10.3390/diagnostics14171903.
Full textAbstract:
Myocardial revascularization has been known to not affect the prognosis in some patients. Coronary artery bypass graft (CABG) failure may develop one year after CABG surgery. This is accompanied by a high risk of developing myocardial infarction after complete myocardial revascularization in obstructive coronary artery disease (CAD) due to microvascular dysfunction. The study of microvascular dysfunction using intraoperative stress tests with adenosine triphosphate (ATP) allows for the assessment of the coronary bypass flow reserve (CBFR) and the risk of graft failure one year after surgery. The study included 79 CAD patients (238 grafts) who underwent dynamic single-photon emission computed tomography (SPECT) before CABG and dynamic transit time flow measurement (TTFM) during CABG at rest and at stress. The CBFR was calculated by the ratio of the mean graft flow (MGF) at stress to the MGF at rest. A multivariate regression model showed that the MGF at rest (p = 0.043), the MGF at stress (p = 0.026) and the CBFR (p = 0.0001) were significant independent predictors of graft failure. As a result of ROC analysis, the threshold CBFR < 1.67 units correlated with graft failure more closely (sensitivity 82%, specificity 90%) The CBFR is a significant independent predictor of graft failure for up to 16 months.
49
Zhao, Caiyou, Dongya Liu, Xiaoming Zhang, Qiang Yi, Liuchong Wang, and Ping Wang. "Influence of Vibration Isolator Failure on Vehicle Operation Performance and Floating Slab Track Structure Vibration Reduction Effectiveness." Shock and Vibration 2019 (June 20, 2019): 1–14. http://dx.doi.org/10.1155/2019/8385310.
Full textAbstract:
At present, steel-spring floating slabs have been widely used in urban rail transit to reduce the influence of ground vibration caused by vehicle operation on the surrounding environment. As a core part of vibration reduction for floating slab track, the steel-spring vibration isolator may fail in different forms during operation. In order to study the influence of vibration isolator failure on vehicle operation performance and floating slab track structure vibration reduction effectiveness, a rigid-flexible coupling dynamic model of vehicle-rail-floating slab track is established by multibody dynamics and finite element simulation, and the rationality of the model and its parameters is verified by comparing the theoretical calculation results with the measured data. Based on the model, the failure conditions of steel spring are simulated, considering the failure position and number of steel springs. The results show that the failures of steel-spring vibration isolators have a significant impact on operating safety and stability of vehicle, and the failure at end is more dangerous than that at midspan. In addition, it also changes the local restraint state of floating slab, resulting in the local vibration mode, which reduces the floating slab track structure vibration reduction effectiveness, mainly within 10 Hz. The different numbers of steel-spring failures will change the natural modal frequency of floating slab to varying degrees, which may cause the resonance of a certain frequency of the vehicle-track coupling system, leading to other track structure diseases.
50
Gilbert, Gregory J. "Accurate Modeling of Grazing Transits Using Umbrella Sampling." Astronomical Journal 163, no. 3 (2022): 111. http://dx.doi.org/10.3847/1538-3881/ac45f4.
Full textAbstract:
Abstract Grazing transits present a special problem for statistical studies of exoplanets. Even though grazing planetary orbits are rare (due to geometric selection effects), for many low to moderate signal-to-noise ratio cases, a significant fraction of the posterior distribution is nonetheless consistent with a grazing geometry. A failure to accurately model grazing transits can therefore lead to biased inferences even for cases where the planet is not actually on a grazing trajectory. With recent advances in stellar characterization, the limiting factor for many scientific applications is now the quality of available transit fits themselves, and so the time is ripe to revisit the transit fitting problem. In this paper, we model exoplanet transits using a novel application of umbrella sampling and a geometry-dependent parameter basis that minimizes covariances between transit parameters. Our technique splits the transit fitting problem into independent Monte Carlo sampling runs for the grazing, nongrazing, and transition regions of the parameter space, which we then recombine into a single joint posterior probability distribution using a robust weighting scheme. Our method can be trivially parallelized and so requires no increase in the wall clock time needed for computations. Most importantly, our method produces accurate estimates of exoplanet properties for both grazing and nongrazing orbits, yielding more robust results than standard methods for many common star–planet configurations.