scholarly journals Navigational Traffic Conflict Technique: A Proactive Approach to Quantitative Measurement of Collision Risks in Port Waters

2009 ◽  
Vol 63 (1) ◽  
pp. 137-152 ◽  
Author(s):  
Ashim Kumar Debnath ◽  
Hoong Chor Chin
Keyword(s):  
Safety Assessment ◽  
Quantitative Measurement ◽  
Safety Analysis ◽  
Collision Risk ◽  
Promising Alternative ◽  
Proactive Approach ◽  
Alternative Approach ◽  
Traffic Conflict

Navigational safety analysis relying on collision statistics is often hampered because of the low number of observations. A promising alternative approach that overcomes this problem is proposed in this paper. By analyzing critical vessel interactions this approach proactively measures collision risk in port waters. The proposed method is illustrated for quantitative measurement of collision risks in Singapore port fairways, and validated by examining correlations between the measured risks with those perceived by pilots. This method is an ethically appealing alternative to the collision-based analysis for fast, reliable and effective safety assessment, thus possessing great potential for managing collision risks in port waters.

An Online Quantified Safety Assessment Method for Train Service State Based on Safety Region Estimation and Hybrid Intelligence Technologies

2015 ◽  
Vol 25 (03) ◽  
pp. 493-511
Author(s):  
Yong Qin ◽  
Shan Yu ◽  
Yuan Zhang ◽  
Limin Jia ◽  
Xiaoqing Cheng
Keyword(s):  
Safety Assessment ◽  
Safety Analysis ◽  
Assessment Method ◽  
Rolling Bearings ◽  
Safety Risk ◽  
Hybrid Intelligence ◽  
Local Mean ◽  
Interval Type ◽  
Service State

Facing the important issues of safety analysis and assessment for the train service state, an online quantified safety assessment method based on the safety region estimation and hybrid intelligence technologies was proposed in this paper. First, the previous researches on the safety analysis and assessment were briefly reviewed for the train itself and its key equipment, and the existential problems were further pointed out. Then, using the safety monitoring data and the safety region estimation theory, a new online safety assessment method with data-driven was put forward, which was followed by a detailed description of the concrete implementation steps including the EMD (Local Mean Decomposition) and EM (Energy Moment) based safety risk evaluation index selection, Interval Type 2 Fuzzy C-Means (IT2FCM) clustering based safety region boundary calculation modeling and safety risk grading. Finally, in order to verify its performance through experiments, the above method was applied in analyzing and evaluating service states of the rolling bearings, the key equipment of the train, on the basis of mass field data. The experimental results indicate that this method is valid.

scholarly journals Virulence-Inhibiting Herbal Compound Falcarindiol Significantly Reduced Mortality in Mice Infected with Pseudomonas aeruginosa

Antibiotics ◽  
2020 ◽  
Vol 9 (3) ◽  
pp. 136 ◽  
Author(s):  
Pansong Zhang ◽  
Qiaolian Wu ◽  
Lin Chen ◽  
Kangmin Duan
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Type Iii Secretion ◽  
Pathogenic Bacteria ◽  
Secretion System ◽  
Chinese Herbs ◽  
Drug Candidate ◽  
Swarming Motility ◽  
Promising Alternative ◽  
Alternative Approach ◽  
Herbal Compound

Antipathogenic compounds that target the virulence of pathogenic bacteria rather than their viability offer a promising alternative approach to treat infectious diseases. Using extracts from 30 Chinese herbs that are known for treating symptoms resembling infections, we identified an active compound falcarindiol from Notopterygium incisum Ting ex H. T. Chang that showed potent inhibitory activities against Pseudomonas aeruginosa multiple virulence factors. Falcarindiol significantly repressed virulence-related genes, including the type III secretion system (T3SS); quorum sensing synthase genes lasIR and rhlIR; lasB; motility-related genes fliC and fliG; and phenazine synthesis genes phzA1 and phzA2. P. aeruginosa swarming motility and pyocyanin production were reduced significantly. In a burned mouse model, falcarindiol treatment significantly reduced the mortality in mice infected with P. aeruginosa, indicating that falcarindiol is a promising antipathogenic drug candidate for treating P. aeruginosa infections.

scholarly journals Progress in Synthesizing Analogues of Nitrogenase Metalloclusters for Catalytic Reduction of Nitrogen to Ammonia

Catalysts ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 939
Author(s):  
Yang
Keyword(s):  
Energy Consumption ◽  
Catalytic Reduction ◽  
High Energy ◽  
Ambient Conditions ◽  
Promising Alternative ◽  
Fossil Energy ◽  
Alternative Approach ◽  
Increasing Demand ◽  
High Energy Consumption ◽  
Significant Opportunity

Ammonia (NH3) has played an essential role in meeting the increasing demand for food and the worldwide need for nitrogen (N2) fertilizer since 1913. Unfortunately, the traditional Haber–Bosch process for producing NH3 from N2 is a high energy-consumption process with approximately 1.9 metric tons of fossil CO2 being released per metric ton of NH3 produced. As a very challenging target, any ideal NH3 production process reducing fossil energy consumption and environmental pollution would be welcomed. Catalytic NH3 synthesis is an attractive and promising alternative approach. Therefore, developing efficient catalysts for synthesizing NH3 from N2 under ambient conditions would create a significant opportunity to directly provide nitrogenous fertilizers in agricultural fields as needed in a distributed manner. In this paper, the literature on alternative, available, and sustainable NH3 production processes in terms of the scientific aspects of the spatial structures of nitrogenase metalloclusters, the mechanism of reducing N2 to NH3 catalyzed by nitrogenase, the synthetic analogues of nitrogenase metalloclusters, and the opportunities for continued research are reviewed.

scholarly journals Surrogate Safety Analysis of Pedestrian-Vehicle Conflict at Intersections Using Unmanned Aerial Vehicle Videos

2017 ◽  
Vol 2017 ◽  
pp. 1-12 ◽  
Author(s):  
Peng Chen ◽  
Weiliang Zeng ◽  
Guizhen Yu ◽  
Yunpeng Wang
Keyword(s):  
Data Extraction ◽  
Cost Effective ◽  
Safety Analysis ◽  
Conflict Analysis ◽  
Unmanned Aerial Systems ◽  
Trajectory Data ◽  
High Exposure ◽  
Safety Issues ◽  
Traffic Conflict ◽  
Aerial Systems

Conflict analysis using surrogate safety measures (SSMs) has become an efficient approach to investigate safety issues. The state-of-the-art studies largely resort to video images taken from high buildings. However, it suffers from heavy labor work, high cost of maintenance, and even security restrictions. Data collection and processing remains a common challenge to traffic conflict analysis. Unmanned Aerial Systems (UASs) or Unmanned Aerial Vehicles (UAVs), known for easy maneuvering, outstanding flexibility, and low costs, are considered to be a novel aerial sensor. By taking full advantage of the bird’s eye view offered by UAV, this study, as a pioneer work, applied UAV videos for surrogate safety analysis of pedestrian-vehicle conflicts at one urban intersection in Beijing, China. Aerial video sequences for a period of one hour were analyzed. The detection and tracking systems for vehicle and pedestrian trajectory data extraction were developed, respectively. Two SSMs, that is, Postencroachment Time (PET) and Relative Time to Collision (RTTC), were employed to represent how spatially and temporally close the pedestrian-vehicle conflict is to a collision. The results of analysis showed a high exposure of pedestrians to traffic conflict both inside and outside the crosswalk and relatively risking behavior of right-turn vehicles around the corner. The findings demonstrate that UAV can support intersection safety analysis in an accurate and cost-effective way.

Application of Extreme Value Theory for Before-After Road Safety Analysis

2019 ◽  
Vol 2673 (4) ◽  
pp. 1001-1010 ◽  
Author(s):  
Lai Zheng ◽  
Tarek Sayed
Keyword(s):  
Extreme Value Theory ◽  
Safety Analysis ◽  
Value Theory ◽  
Extreme Value ◽  
Data Traffic ◽  
Crash Data ◽  
Safety Improvement ◽  
Traffic Conflicts ◽  
Traffic Conflict ◽  
Generalized Pareto Distributions

Because of well-recognized quality and quantity problems associated with historical crash data, traffic conflict techniques have been increasingly used in before-after safety analysis in recent years. This study proposes using an extreme value theory (EVT) approach to conduct traffic conflict-based before-after analysis. The capability of providing confident estimation of extreme events by the EVT approach drives the before-after analysis to shift from normal traffic conflicts to more serious conflicts, which are relatively rare but have more in common with actual crashes. The approach is applied to evaluate the safety effects of converting channelized right-turn lanes into smart channels, based on traffic conflicts defined by time to collision (TTC) and collected from three treatment intersections and one control intersection in the city of Penticton, British Columbia. Odds ratios and treatment effects are calculated from extreme-serious conflicts, the frequencies of which are estimated from the generalized Pareto distributions of traffic conflicts with TTC⩽0.5 s. The results show approximately 34% reduction in total extreme-serious conflicts (i.e., combining merging conflicts and rear-end conflicts), indicating overall a remarkable safety improvement following the smart channel treatment. This finding is consistent with the analysis result based on traffic conflicts with TTC⩽3.0 s. It is also found that the reduction in extreme-serious merging conflicts is small and insignificant. This is caused by the phenomenon that TTC values of merging conflicts become smaller after the treatment, and it is possibly because drivers become more aggressive with the better view of approaching cross-street traffic provided by the smart channel.

scholarly journals Road safety assessment in preferential bus lanes through field analysis and microsimulation of traffic conflicts

2019 ◽  
pp. 87-100 ◽  
Author(s):  
Julián Darío Julián Otero-Niño ◽  
Juan David Heredia-Castiblanco ◽  
Paula Daniela Fonseca-Agudelo ◽  
Sebastián Cabrera-Pinzón ◽  
Alejandro Gómez-Mosquera ◽  
...  
Keyword(s):  
Public Transport ◽  
Road Safety ◽  
Safety Assessment ◽  
Stopping Time ◽  
Field Analysis ◽  
Road Users ◽  
Traffic Conflicts ◽  
Traffic Conflict ◽  
Field Information ◽  
The One

Preferential bus lanes are a widely use strategy to promote travelers to use public transport instead of private cars. Considering its relevance in the urban transportation planning and operation, it is crucial to evaluate them in terms of the operation and safety externality. We performed a road safety assessment in preferential public transport lanes with complex driving environment using a preventive approach on the 7 th Avenue, in Bogota (Colombia), between 39 th Street and 45 th Street. A detailed study of traffic conflicts was carried out under the guidelines of the Swedish technique, which uses the Time to accident and Conflicting speed to establish the severity of a conflict. A traffic conflict is defined as an incident where, if two road users on collision course maintain their speed and trajectory constant, the crash between them will be imminent. With the field information, we calibrated a VISSIM microsimulation model that correctly replicates its traffic operation. Using the SSAM tool, we validated the base model to identify the simulated traffic conflicts in VISSIM and compared them with the observed conflicts. Under the calibrated environment, we developed and assessed three different scenarios of countermeasures to reduce the number of conflicts observed. As a result, we found that the safest scenario is the one established in the regulations that normalize the operation in preferential lanes, currently not obeyed by most users. Based on our results, we recommend an adjustment in the normative measures, including regulating the stopping time and stopping zones of private vehicles and taxis.

Longitudinal Collision Risk Assessment of Paired Departure to Closed Spaced Parallel Runways

2014 ◽  
Vol 1030-1032 ◽  
pp. 2028-2033
Author(s):  
Zhao Ning Zhang ◽  
Hui Qiao ◽  
Ting Ting Lu
Keyword(s):  
Risk Assessment ◽  
Traffic Control ◽  
Air Traffic Control ◽  
Safety Assessment ◽  
Error Distribution ◽  
Air Traffic ◽  
Assessment Model ◽  
Collision Risk ◽  
Safety Operation ◽  
Calculation Models

Paired departure to closed spaced parallel runways can effectively improve capacity of terminal, and also can solve congestion of busy airport, but it also increases the complexity of air traffic control .For ensuring safety operation of paired departure, the longitudinal collision risk of paired departure to closed spaced parallel runways was studied. Based on the acceleration error distribution and requirements on wake avoidance during paired departure, a longitudinal collision risk safety assessment model of closed spaced parallel runways paired departure was built. The parameters in this model were determined by providing the calculation models. In the end, an example was calculated to verify the model, and it turns out that this model is feasible.

Offshore Safety Assessment and Safety-Based Decision-Making—The Current Status and Future Aspects

1999 ◽  
Vol 122 (2) ◽  
pp. 93-99 ◽  
Author(s):  
J. Wang ◽  
O. Kieran
Keyword(s):  
Decision Making ◽  
Safety Assessment ◽  
Safety Analysis ◽  
Current Status ◽  
Safety Critical ◽  
Critical Elements ◽  
Offshore Installations ◽  
Safety Case ◽  
The Uk ◽  
Further Development

The offshore installations (safety case) regulations were developed in the UK in 1992 and came into force in 1993 in response to the accepted findings of the Piper Alpha enquiry. Recently, “the offshore installations and wells (design and construction, etc.) regulations” (DCR 1996) were introduced to offshore safety analysis. From the earliest stages of the installation’s life cycle, operators must ensure that all safety-critical elements in both the software and system domains be assessed. Hazards can be identified and the risks associated with them can be assessed and evaluated using a number of techniques and decision-making strategies, all aimed at producing an installation with lifetime safety integrity. In this paper, following a brief review of the current status of offshore safety regulation in the UK, several offshore safety assessment frameworks are presented. These include top-down, bottom-up, probabilistic, and subjective approaches. The conditions under which each approach may be applied effectively and efficiently are discussed. Probabilistic safety-based decision-making and subjective safety-based decision-making are then studied. Two examples are used to demonstrate the decision-making approaches. Recommendations on further development in offshore safety analysis are suggested. [S0892-7219(00)00901-8]

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