A new method for calibration of unidirectional double-peak spectra

This study aims at presenting a new approach in calibrating standard two-peak design spectra for specific regions in absence of wind data. The main principle in these kinds of fitting for a new area is to minimize the least square error between measured and fitted spectra and there has been less attention to double-peak spectra individual characteristic as co-existence of wind-sea and swell parts in one spectrum. Here, separation frequency, approximately dividing such parts, is implemented to virtually extract wind-sea and swell components of a measured spectrum considering their intrinsic overlap near the separation frequency. Then, they have been easily utilized to calibrate two parts of standard double-peak spectrum in a revisory manner. To verify benefits of this new methodology, it has been applied on Ochi-Hubble as well as Torsethaugen spectra regarding field measurements in a coastal region at Gulf of Oman, Chabahar bay. Results obviously show a better adjustment of formula to field spectrum using this simple approach when compared with output of calibration on integrated field spectrum irrespective of its main characteristic such as availability of two-wave systems.     

Influence of Governance Context on the Management Performance of Marine Protected Area Networks

In the Philippines, networks of marine protected areas (MPAs) are more complex than individual MPAs, primarily due to involvement of multiple governance units. Hence, there is a need to understand the influence of governance context of networks on management performance. We addressed this need indirectly by evaluating the participation of network members and the governance capacity of three MPA networks with varying sizes, histories, and compositions of local governments and constituencies. We defined participation as the involvement of local governments and other stakeholders in decision-making processes. We defined governance capacity as the ability to govern interactions of social, economic, and political processes and dynamics in a political unit. We used qualitative, semi-structured key informant interviews and focus group discussions to ascertain whether participation and governance capacity are influenced by network size, institutional arrangements, and social and political contexts. We found that the sizes of the MPA networks did not affect participation and governance capacity. Instead, participation and capacity were influenced by institutional arrangements and the socioeconomic and political contexts of the local governments involved. We found that less complicated network objectives and systems for engagement, more inclusive membership, better communication, incentive systems, and strong leadership enhanced participation and governance capacity.     

Fixed‐route taxi system: route network design and fleet size minimization problems

This paper introduces the taxi route network design problem (TXRNDP) for a fixed‐route taxi service operating in Iran and, in similar form, in various other developing countries. The service operates fairly similar to regular transit services in that vehicles are only permitted to follow a certain predetermined route on the network. The service is provided with small size vehicles and main features are that vehicles only depart if full and that there are no intermediate boarding stops. In Iran the service attracts a high modal share but requires better coordination which is the main motivation for the present study. We develop a mathematical programming model to minimize the total travel time experienced by passengers while constraining the number of taxi lines, the trip transfer ratio and the length of taxi lines. A number of assumptions are introduced in order to allow finding an exact rather than heuristic solution. We further develop a linear programming solution to minimize the number of taxis required to serve the previously found fixed‐route taxi network. Results of a case study with the city of Zanjan, Iran, illustrate the resulting taxi flows and suggest the capability of the proposed model to reduce the total travel time, the total waiting time and the number of taxi lines compared to the current taxi operation. Copyright © 2016 John Wiley & Sons, Ltd.     

Vehicle sharing system with fleet sizing and multi-transportation modes under allowable shortages: a hybrid metaheuristic approach

In this paper, a vehicle sharing system with multi-transportation modes and allowable shortage is presented. This model aims to minimize the system's total cost by using optimum locations and number of stations, routes, transportation modes, station capacities for different modes and time between stations balancing. Because of the model's complexity, currently available proprietary software is not able to solve the model in a reasonable computational time, so a hybrid algorithm based on a genetic algorithm (GA) and particle swarm optimization is presented. The results confirm its efficiency compared with the classic GA and exact solution methods. Moreover, a sensitivity analysis shows the applicability of the proposed algorithm.     

A simulation optimization approach for solving the dual-cycling problem in container terminals

Dual cycling is an operation technique whereby quay cranes perform loading and unloading operations simultaneously in the same ship bay. In this article, a mixed-integer programming model for quay crane dual-cycling scheduling is developed. The model considers the stowage plan of outbound containers and the operation sequence of quay cranes. To solve the model, a heuristic method, called bi-level genetic algorithm, is designed. Meanwhile, a simulation optimization method integrating the intelligent decision mechanism of the optimization algorithm and evaluation function of simulation model is proposed. Numerical experiments indicate that dual cycling can reduce the operation time of quay cranes compared to the method of scheduling loading and unloading separately. Moreover, the model and algorithms developed in this article can tackle quay crane dual-cycling problem efficiently.     

Resistance analysis of a semi-SWATH design concept in shallow water

Resistance analysis is an important analytical method used to evaluate the hydrodynamic performance of High Speed Craft (HSC). Analysis of multihull resistance in shallow water is essential to the performance evaluation of any type of HSC. Ships operating in shallow water experience increases in resistance because of changes in pressure distribution and wave pattern. In this paper, the shallow water performance of an HSC design concept, the semi-Small Waterplane Area Twin Hull (semi-SWATH) form, is studied. The hull is installed with fin stabilizers to reduce dynamic motion effects, and the resistance components of the hull, hull trim condition, and maximum wave amplitude around the hull are determined via calm water resistance tests in shallow water. These criteria are important in analyzing semi-SWATH resistance in shallow water and its relation to flow around hull. The fore fin angle is fixed to zero degrees, while the aft fin angle is varied to 0°, 5°, 10°, and 15°. For each configuration, investigations are conducted with depth Froude numbers (Fr _H ) ranging from 0.65 to 1.2, and the resistance tests are performed in shallow water at the towing tank of UTM. Analysis results indicate that the resistance, wave pattern, and trim of the semi-SWATH hull form are affected by the fin angle. The resistance is amplified whereas the trim and sinkage are reduced as the fin angle increases. Increases in fin angle contribute to seakeeping and stability but affect the hull resistance of HSCs.     

Direct generation of level of service maps from images using convolutional and long short-term memory networks

Congestion in transport stations could result in stampede development and deadly crush situations. Closed circuit television (CCTV) cameras enable station managers to monitor the crowd and reduce overcrowding risks. However, identifying congestion conditions is a very laborious task for a human operator who has to monitor multiple locations at the same time. This paper presents a new approach to automated image-based identification of congestion as measured by level of service (LOS), which is the most widely accepted standard for measuring congestion. Existing methods for measuring LOS based on crowd density estimation from images have the disadvantages that, crowd density cannot be estimated accurately. In addition, the calculation of flow parameters involves a complex process, and consequently these parameters are not indicative of congestion in real-time. This paper proposes a novel method based on machine learning to directly classify LOS without calculating flow parameters. In the proposed method, visual features extracted by a deep convolutional neural network are classified using a support vector machine classifier and the classification results are further refined by using a long short-term memory network. A second contribution of this research is to develop a web-based LOS map visualization platform to monitor pedestrian distribution and variation of distribution in real-time. Experimental evaluation at Flinders Street Station in Melbourne shows that this method can achieve an accuracy of 81.9% and efficiency of 0.40?seconds per frame in LOS classification using CCTV images.     

Pedestrian crowd tactical‐level decision making during emergency evacuations

This paper investigates pedestrian crowd tactical‐level decision making during emergency evacuations. Of particular interest is crowd exit‐choice behaviour. Two sources of stated choice data are collected and combined. One data set is derived from an experiment linked to a real‐life exit choice experience of participants (in a non‐evacuation setting). We examine aspects that have often been taken for granted in the literature in connection with egress behaviour of crowds during emergencies. We quantify evacuees' trade‐off between “distance”, “density”, “exit visibility” and “directional density” as well as the interactive effect between exit visibility and tendency to follow others. A comprehensive random‐utility analysis is conducted ranging from traditionally practiced models to the state‐of‐the‐practice methods such as random‐coefficient nested logit. Our findings suggest that (i) unless evacuees face certain levels of uncertainty in the escape environment; flows of crowd are unlikely to be followed. Otherwise, most evacuees perceive other individuals as potential sources of congestion and extra delay (generalisation to situations where crowd is completely unfamiliar with the egress geometry, however, may require careful scrutiny). (ii) Evacuees mostly prefer visible exits over the exits whose congestion level is unknown to them (i.e. the tendency to minimise ambiguity). (iii) The presence of attribute uncertainty (e.g. exit visibility) significantly changes the impact of observing decisions of others on each individual choice maker. We also found out that (iv) spatial distribution of exits has a significant influence on evacuees' decisions (presenting itself in the form of violating the IIA assumption). (v) The marginal weights that different individuals place upon attributes of exits are significantly heterogeneous. (vi) There is meaningful correlation between certain utility weights of individual evacuees. These behavioural findings can provide significant behavioural insight essential for safe evacuation planning and accurate forecast of evacuees' behaviour. Copyright © 2016 John Wiley & Sons, Ltd.     

Innovative detector layout for automated traffic turning volume counting

Because of many advantages, loop detectors are the most common practice for obtaining data to control intersections. However, they have some drawbacks, including the fact that multiple detectors are usually required to monitor a location. The current practice in many cities is to install four consecutive loop detectors per lane, or two at the stop bar and one as an advanced detector. In some cities, there are also departure detectors. All these configurations have some practical problems and do not produce accurate counts especially in shared lanes. In this paper, a new placement configuration for departure detectors is proposed and named the mid‐intersection detector (MID). In this configuration, departure detectors are moved back to the middle of the intersection in such a way that they can be activated by more than one movement at different times. In some cases, departure detectors lack equations for calculating turning movements, a problem solved by MIDs because each movement passes more detectors along its path (without increasing the number of loops), and therefore they can produce more accurate and reliable data for obtaining turning movement counts. Copyright © 2017 John Wiley & Sons, Ltd.     

Analysis of thirty years evolution of urban growth,transport demand and supply,energy consumption,greenhouse and pollutants emissions in Greater Cairo

The objective of the paper is to analyze evolution of urbanization, transport demand and supply in Greater Cairo (GC) over the last three decades of the 20th century. This is in addition to investigating the impact of city growth on energy consumption and emissions from transport. It utilizes results of 1971, 1978, 1987, 1998 and 2001 travel demand surveys, undertaken during the corresponding GC transport studies; each was published a year or two later. No further transport studies have been carried out in GC over the past decade and in view of the current political situation, it is not envisaged that similar studies will be undertaken in the near future. The analysis includes the evolution of daily trips, trip purpose share, modal share and number of cars. More recent trends for 2006/2007 vehicle registration by type and size are given. The evolution of transport supply covers projects until early 2012. In parallel estimates of the evolution of energy consumption and cost, emissions of greenhouse gases (CO₂) and pollutants (CO, HC and NO_x) are given for 1971/2001. The adopted estimation methodology is summarized. Comparative analysis of relevant evolution indexes and trends of growth between 1971 and 2001, taking the former as base year, is given. Land use and transport policies and projects that in some cases helped, directly or indirectly, to reduce traffic congestion, or at least prevented an increase, are addressed, commenting on their outcomes. Thus, transferable experience are useful to sister cities benefiting from successes and avoiding drawbacks. The evolution of the impact of GC metro on energy consumption and cost, and GHG emissions is given for 1987/2001, assuming the scenario “metro did not exist”. More recent impact analysis is given for 2007/2008, as the data allowed estimating traffic volumes that would have been added to the congested metro corridors under the above scenario; and the related fuel consumption and cost and GHGs. The paper ends with conclusions on GC evolution, learned lessons and suggests repeating similar work in other mega cities of the developing countries. Further research is emphasized, e.g., modeling the relationship between land use, transport, energy and emissions; modeling emission factors by vehicle type; and studying fuel-subsidy-reduction scenarios and their socio-economic effects.