Toll Estimation as a Function of Time-Dependent Link Cost, Vehicle Category and Distance–A Case Study for Karachi

2016 ◽  
Author(s):  
Mir S. Ali ◽  
◽  
Muhammad Adnan ◽  
Syed F. A. Baqueri
Keyword(s):  
Time Dependent ◽  
Vehicle Category ◽  
Link Cost ◽  
Dependent Link

Multiclass, Multicriteria Dynamic Traffic Assignment with Path-Dependent Link Cost and Entropy-Based Risk Preference

2017 ◽  
Vol 2667 (1) ◽  
pp. 108-118 ◽  
Author(s):  
Jiangbo Gabriel Yu ◽  
R. Jayakrishnan
Keyword(s):  
Travel Time ◽  
Traffic Assignment ◽  
Dynamic Traffic Assignment ◽  
Dynamic Traffic ◽  
Time Uncertainty ◽  
Link Cost ◽  
Travel Time Uncertainty ◽  
Path Dependent ◽  
Dependent Link

Challenges arise in dynamic traffic assignment (DTA) when heterogeneous users evaluate choices on the basis of multiple interrelated criteria such as travel time and travel time uncertainty. This paper proposes a density-based formulation along with a stochastic quasigradient projection (SQGP) solution scheme with the aid of a traffic simulator. Path-dependent link cost is proposed to allow for the objective function formulation and more tractable analysis. The criteria in the discussion and the case study are travel time (link-additive), monetary cost (non additive), and travel time uncertainty (path-dependent link-additive). An information entropy-based uncertainty measure is proposed because of concerns about using conventional measures such as variability and reliability. The case study shows stochastic and efficient convergence, demonstrates the ability of SQGP to bypass local optima, and exemplifies the significant effect of using path-independent and path-dependent link costs to forecast traffic pattern and toll revenue. The results also suggest that a pricing strategy aimed at optimizing travel time and reliability for different user classes should consider travel time correlations between toll segments and the adjacent no-toll segments if enumerating paths is practically infeasible.

Safety Assessment of Long Term Serviced Pressure Vessels: A Case Study of Typical Refining and Chemical Plants in China

2021 ◽  
Author(s):  
Zhiyuan Han ◽  
Guoshan Xie ◽  
Haiyi Jiang ◽  
Xiaowei Li
Keyword(s):  
Pressure Vessel ◽  
Safety Assessment ◽  
Failure Modes ◽  
Pressure Vessels ◽  
Time Dependent ◽  
Chemical Plants ◽  
Safety Specification ◽  
Detailed Assessment

Abstract The safety and risk of the long term serviced pressure vessels, especially which serviced more than 20 years, has become one of the most concerned issues in refining and chemical industry and government safety supervision in China. According to the Chinese pressure vessel safety specification TSG 21-2016 “Supervision Regulation on Safety Technology for Stationary Pressure Vessel”, if necessary, safety assessment should be performed for the pressure vessel which reaches the design service life or exceeds 20 years without a definite design life. However, the safety and risk conditions of most pressure vessels have little changes after long term serviced because their failure modes are time-independent. Thus the key problem is to identify the devices with the time-dependent failure modes and assess them based on the failure modes. This study provided a case study on 16 typical refining and chemical plants including 1870 pressure vessels serviced more than 20 years. The quantitative risk and damage mechanisms were calculated based on API 581, the time-dependent and time-independent failure modes were identified, and the typical pressure vessels were assessed based on API 579. Taking the high pressure hydrogenation plant as an example, this study gave the detailed assessment results and conclusions. The results and suggestions in this study are essential for the safety supervision and extending life of long term serviced pressure vessels in China.

scholarly journals Development of driving cycle under real world traffic conditions: A case study

2019 ◽  
Vol 9 (6) ◽  
pp. 4798
Author(s):  
Geetha A. ◽  
Subramani C.
Keyword(s):  
Driving Cycle ◽  
Time Dependent ◽  
Maximum Speed ◽  
Time Data ◽  
Maximum Acceleration ◽  
The Road ◽  
Traffic Conditions ◽  
Condensed Form ◽  
On The Road

<p><span>The modeling of a car is essentially done by taking into consideration the driving terrain, traffic conditions, driver’s behavior and various other factors which may directly or indirectly affect the vehicle’s performance. A vehicle is modeled for given specifications and constraints like maximum speed, maximum acceleration, and braking time, appropriate suspension for the gradient of the road and fuel consumption. Henceforth, a profound study and analysis of different drive cycles are essential. A time dependent drive cycle is a condensed form of data that helps us to determine the time taken to conduct the driving test on the road. This article highlights the development of a real driving cycle in the area of Tamilnadu, India. On-road vehicle’s speeds versus time data were obtained along the selected route. The data obtained were analyzed first and then a new driving cycle was developed.</span></p>

Evaluation of Aerodynamic Characteristics of Mega-Yacht Superstructures by CFD Simulations

2020 ◽  
Vol 36 (04) ◽  
pp. 259-270
Author(s):  
Ahmet Ziya Saydam ◽  
Serhan Gokcay ◽  
Mustafa Insel
Keyword(s):  
Aerodynamic Characteristics ◽  
Temperature Gradients ◽  
Time Dependent ◽  
Navier Stokes ◽  
Noise Generation ◽  
Velocity Data ◽  
Cfd Simulations ◽  
Recent Developments ◽  
Computational Fluid Dynamics Cfd

Air wake distribution around the superstructure of a mega-yacht is a key concern for the designer because of various reasons such as comfort expectations in recreational deck areas, self-noise generation, air pollution and temperature gradients due to exhaust interactions, and safety of helicopter operations such as landing/take off and hovering. The Reynolds-averaged Navier-Stokes (RANS) technique in computational fluid dynamics (CFD) is frequently used in studies on mega-yacht hydrodynamics and aerodynamics with satisfactory results. In this article, a case study is presented for the utilization of CFD in a mega-yacht's superstructure design. The flow field in recreational open areas has been analyzed for the increase in velocity due to the existence of the superstructure. A reduction in self-noise of the mast structure has been aimed by reducing flow separation and vorticity. Time-dependent velocity data obtained with scale-resolving simulations are presented for the evaluation of helicopter landings. The capabilities and limitations of the RANS technique are discussed along with recent developments in modeling approaches.

A Three-Dimensional Time-Dependent Icing Model for a Stern Trawler

1998 ◽  
Vol 42 (04) ◽  
pp. 266-273
Author(s):  
K. K. Chung ◽  
E. P. Lozowski
Keyword(s):  
Three Dimensional ◽  
Grid Cell ◽  
Full Scale ◽  
Time Dependent ◽  
Trajectory Modeling ◽  
Model Scale ◽  
Droplet Trajectory ◽  
Dangerous Condition

A full-scale spray flux equation has been derived for ship-generated spray using spraying data obtained from model-scale experiments. Using this equation, droplet trajectory modeling, and spray mass continuity, a full-scale spraying model, which includes the effect of wind drag, has been developed for the stern trawler Zandberg. This spraying model has been incorporated into an icing model for the same vessel. A three-dimensional grid cell mesh is superimposed on the surface of the ship so that the local spray flux and icing rate on each grid cell can be calculated using the combined spraying and icing models. The disappearance of the Blue Mist II is used as a case study to illustrate the performance of the icing model. Under these severe icing conditions with off-head winds, the model predicts an icing rate of more than 13 tonnes per hour for the Zandberg, and the ice distribution is highly asymmetrical. This ice loading is the most dangerous condition for the ship's stability.

Case studies considering the influence of the time-dependent behaviour of concrete on the serviceability limit state design of composite steel-concrete buildings

2021 ◽  
pp. 137-156
Author(s):  
Alejandro Pérez Caldentey ◽  
John Hewitt ◽  
John van Rooyen ◽  
Graziano Leoni ◽  
Gianluca Ranzi ◽  
...  
Keyword(s):  
Case Studies ◽  
Limit State ◽  
Time Dependent ◽  
Commercial Building ◽  
Time Effects ◽  
Concrete Buildings ◽  
Time Dependent Behaviour ◽  
Dependent Behaviour ◽  
Composite Steel

<p>This chapter presents a number of case studies that deal with the service design of composite steel-concrete buildings associated with the time-dependent behaviour of the concrete. The particular focus of this chapter is to outline key design aspects that need to be accounted for in design and that are influenced by concrete time effects. The first case study provides an overview of the design considerations related to the time-dependent column shortening in typical multi-storey buildings by considering the layout of the Intesa Sanpaolo Headquarters in Turin as reference. The second case study focuses on a composite floor of a commercial building constructed in Australia and it provides an overview of the conceptual design used to select the steel beam framing arrangement to support the composite floor system while accounting for concrete cracking and time effects. The third case study deals with the Quay Quarter Tower that has been designed for the repurposing of an existing 50-year old building in Australia while accounting for the time-dependent interaction between the existing and the new concrete components of the building.</p>

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