岙山作业区VLCC应急临时锚位选址考虑因素和建议

岙山作业区作为国家战略石油储备基地及原油、成品油中转储运基地,各类油品船及超大型油轮VLCC靠离泊及装卸作业频繁,安全风险较高。本文从水上应急管理、节能增效,提升港口作业服务水平等角度分析建设VLCC应急临时锚位的必要性,以及从政策方面、通航因素、水深底质等方面分析了选址应考虑的因素,并提出了选址建议。     

A queuing model analysis of the performance of the Hong Kong container terminals

The growth of container‐handling industry and its impact on Hong Kong's economy have aroused considerable attention in recent decades. Within the recent twenty years, the rapid growth of container‐handling industry has led Hong Kong to become one of the world's busiest container port with over 11 million T.E.U. s (Twenty Feet Equivalent Units) container throughput in one year period. Also the container throughput is expected to reach 15.5 million T.E.U. s by year 2004.

As the success of container‐handling industry is significant, many studies have been conducted relating to this subject. In this paper, an application of a queuing theory model to Kwai Chung Container Terminals is developed and described. Specifically, we consider seasonal changes at the Terminals and focus on their effects on inter‐arrival time and service time of container vessel.

A crucial component of the study relates to the empirical data collected. Besides verifying the validity of the model, those data provide guidelines for developing schemes to manage the seasonal fluctuation of container throughput of the Terminals.     

Assessing greenhouse gas emissions from port vessel operations at the Port of Incheon

This paper measures greenhouse gas emissions from port vessel operations by considering the case of Korea’s Port of Incheon. It provides estimates of greenhouse gas emissions based on the type and the movement of a vessel from the moment of its arrival, to its docking, cargo handling, and departure. Taking a bottom-up approach based on individual vessels’ characteristics and using data on vessels processed by the port in 2012 estimate emissions. The results indicate that the level of emissions is five times higher than that estimated through the top-down approach. Among various types of vessels, international car ferries are the heaviest emitters, followed by full container vessels and car carriers. A vessel’s passage through lock gates and maneuver to approach the dock accounts for 96% of its emissions. Docking for cargo handling shows the lowest level of GHG emissions.     

In Search of the Link between Ship Size and Operations

Abstract

Since 1990s the liner shipping industry has faced a period of restructuring and consolidation, and been confronted with a continuing increase in container vessel scale. The impact of these changes is noticeable in trade patterns, cargo handling methods and shipping routes, in short ‘operations’. After listing factors influencing size, growth in container ship size is explained by economies of scale in deploying larger vessels. In order to quantify economies of scale, this paper uses the liner service cash flow model. A novelty in the model is the inclusion of +6000-20-foot Equivalent Unit (TEU) vessels and the distinction in costs between single and twin propeller units on ships. The results illustrate that scale economies have been – and will continue to be – the driving force behind the deployment of larger container vessels. The paper then assesses the link between ship size and operations, given current discussions about the increase in container vessel scale. It is found that (a) ship size and operations are linked; (b) optimal ship size depends on transport segment (deep-sea vs. short-sea shipping, SSS), terminal type (transhipment terminals vs. other terminals), trade lane (East-West vs. North-South trades) and technology; and (c) a ship optimal for one trade can be suboptimal for another.     

Control strategies for departure process delays at airport passenger terminals

This paper explores the characteristics of process delays at airport passenger terminals and establishes a queuing model for both passengers and baggage served by different connecting type facilities. The impact of delay propagation on other processes and flights is investigated using an analytical approach. In addition, the extra costs incurred on passengers, process operators, and airlines are examined using the delay cost functions. To reduce the impact of process delays, various delay-controlled strategies are proposed, such as setting scheduled times for completion of a process, increasing the number of service counters, and priority service for emergent flights. Taoyuan International Airport in Taiwan is used as a case study when facing special events. Results showed that the model can effectively and efficiently estimate delay propagation and its costs. In addition, processes that are not consecutive allow more buffer time between different operations, which helps ease propagation of delays caused by previous services.     

Reducing port-related truck emissions: The terminal gate appointment system at the Ports of Los Angeles and Long Beach

Growth in international trade and changing patterns of production have resulted in greatly increased volumes of freight traffic in urban areas. Metropolitan areas serving as major nodes within the international trade network are particularly affected. In California, state regulation was imposed on port operations in an effort to mitigate congestion and air pollution associated with increased port-related trade. This paper presents an evaluation of the outcomes of California Assembly Bill (AB) 2650 at the Ports of Los Angeles and Long Beach. The legislation permitted terminals to adopt either gate appointments or off-peak operating hours as a means of reducing truck queues at gates. There is no evidence of reduced queuing or transaction times, and hence that AB 2650 did not result in reduced truck emissions.     

Border crossing delay prediction using transient multi-server queueing models

As a result of the continued increase in travel demand coupled with the need for tighter security and inspection procedures after September 11, border crossing delay has recently become a critical issue with tremendous economic and social costs. The current paper develops multi-server queuing models to estimate border crossing delay in support of a predictive traveler information system for the crossings. Two classes of multi-server models are considered: (1) models with exponential inter-arrival times and Erlang service times; and (2) a more generic model with a Batch Markovian Arrival Process (BMAP) and phase types (PH) services. As a case study, the models are developed based on real-time traffic volume and inspection time data collected at one of the major US–Canada border crossings, the Peace Bridge, and their transient solution is obtained using heuristic methods. For validation, the queueing models’ estimates are compared to the results from a detailed microscopic traffic simulation model of the Peace Bridge border crossing. The comparison shows that the transient queueing model, along its heuristic solution algorithm, is capable of predicting border crossing delay. Finally, a set of sensitivity analysis tests are conducted, and the developed models are incorporated within an optimization framework to help inform border crossing management strategies.     

Real time queue length estimation for signalized intersections using travel times from mobile sensors

We study how to estimate real time queue lengths at signalized intersections using intersection travel times collected from mobile traffic sensors. The estimation is based on the observation that critical pattern changes of intersection travel times or delays, such as the discontinuities (i.e., sudden and dramatic increases in travel times) and non-smoothness (i.e., changes of slopes of travel times), indicate signal timing or queue length changes. By detecting these critical points in intersection travel times or delays, the real time queue length can be re-constructed. We first introduce the concept of Queue Rear No-delay Arrival Time which is related to the non-smoothness of queuing delay patterns and queue length changes. We then show how measured intersection travel times from mobile sensors can be processed to generate sample vehicle queuing delays. Under the uniform arrival assumption, the queuing delays reduce linearly within a cycle. The delay pattern can be estimated by a linear fitting method using sample queuing delays. Queue Rear No-delay Arrival Time can then be obtained from the delay pattern, and be used to estimate the maximum and minimum queue lengths of a cycle, based on which the real-time queue length curve can also be constructed. The model and algorithm are tested in a field experiment and in simulation.     

A G/G(n)/C/C state‐dependent simulation model for metro station corridor width design

Metro station corridor and passengers are described as a G/G(n)/C/C state‐dependent queuing system with a general random arrival interval G and a general random and state‐dependent service time G(n) to offset the shortcomings in existing design methods. The corresponding G/G(n)/C/C state‐dependent discrete event simulation model is developed, and its high‐fidelity is tested. Then the optimization algorithm based on the simulation model is designed to determine corridor width. The proposed simulation optimization method and the existing analytical optimization methods, based on M/G(n)/C/C and D/D/1/C queuing models, are applied to design corridor width in a numerical example of 48 combinations of passenger flow rates and level of service (LOS). The designed corridor widths are tested in a micro‐simulation model, and the performance measure is compared. The result shows that the corridor widths obtained by the new method are 0.357 m (7.4%) larger than that of the other two methods on average; the area per passenger of the new method increases 10.53% and 11.63%, respectively, compared with that of the other two methods; the widths designed by the new method satisfy the requirement of LOS under various passenger flows, whereas 93% of the corridor widths obtained by the other two methods fail to meet the requirement of LOS, and the corridor widths designed by the new method have high elasticity coefficients of LOS‐width. Copyright © 2015 John Wiley & Sons, Ltd.     

How do economies of density in container handling operations affect ships’ time and emissions in port? Evidence from Norwegian container terminals

Efficient port services are prerequisites for competitive and sustainable maritime transports. This paper makes advances in studying the determinants of the time that ships spend in port and the associated emissions to air. We estimate a production model for cargo handling based on a unique dataset containing each port of call at the largest container terminals in Norway in 2014. In turn, we use auxiliary engine emission factors to estimate particulate matter and nitrogen oxide emissions from ships at berth, to determine how the corresponding damage costs of air pollution vary with container throughput, location, and terminal investments. We find that Norwegian container terminals operate under increasing returns to density. Small ships that unload few containers are far from reaping economies of density, leading to high marginal time requirements for container handling and consequently high marginal external costs. From a Pigouvian taxation perspective, port charges should therefore be regressive in the number of containers handled. Moreover, we find that the external costs of maritime transports are severely understated when port operations are ignored. Our model allows determining the marginal productivities of port facilities. Thereby, it is instrumental in designing port charges that are diversified according to the quantity of containers handled and the service quality (i.e., the speed of handling operations). Regarding contextual factors, we find that establishing high-frequent liner services improves the ship working rate, while simultaneous calls at a terminal impede productivity. The type of container (loading/unloading; empty/laden) also appears to influence the duration of ship working.     

Greenhouse gas emissions from ships in ports – Case studies in four continents

Emissions of GHG from the transport sector and how to reduce them are major challenges for policy makers. The purpose of this paper is to analyse the level of greenhouse gas (GHG) emissions from ships while in port based on annual data from Port of Gothenburg, Port of Long Beach, Port of Osaka and Sydney Ports. Port call statistics including IMO number, ship name, berth number and time spent at berth for each ship call, were provided by each participating port. The IMO numbers were used to match each port call to ship specifications from the IHS database Sea-web. All data were analysed with a model developed by the IVL Swedish Environmental Research Institute for the purpose of quantifying GHG emissions (as CO₂-equivalent) from ships in the port area. Emissions from five operational modes are summed in order to account for ship operations in the different traffic areas. The model estimates total GHG emissions of 150,000, 240,000, 97,000, and 95,000 tonnes CO₂ equivalents per year for Gothenburg, Long Beach, Osaka, and Sydney, respectively. Four important emission-reduction measures are discussed: reduced speed in fairway channels, on-shore power supply, reduced turnaround time at berth and alternative fuels. It is argued that the potential to reduce emissions in a port area depends on how often a ship revisits a port: there it in general is easier to implement measures for high-frequent liners. Ships that call 10 times or less contribute significantly to emissions in all ports.     

A container terminal simulation model with animation capabilities

The objective of this paper is to introduce a computer simulation model with on-screen animation graphics, which can simulate the operations of a container terminal equipped with straddle carriers. The movements of the equipment are simulated as realistically as possible, to include time losses due to the mismatch in the sequence of equipment movements and to traffic congestion. Trucks are normally served in a specified area, but in some cases, straddle carrier drivers can call the truck to be served directly in the container storage areas. The experience of operators is incorporated in the model, in the form of a knowledge base, that is used to simulate the above process and determine the service discipline. The model was designed to evaluate different configurations (changes in yard layout, equipment number and productivity, truck arrival pattern and service discipline) of the simulated system. The proposed model was used to examine the differences between “the observed” operations strategy and the strategy dictated by the operational rules of the port of Piraeus. The results indicate that “the observed” strategy leads to shorter truck service time but increase the traffic conflicts in the terminal's internal transport networks.     

Bi-objective optimization for the container terminal integrated planning

In this paper, we study the joint optimization of the tactical berth allocation and the tactical yard allocation in container terminals, which typically consist of berth side and yard side operations. The studied two objectives are: (i) the minimization of the violation of the vessels’ expected turnaround time windows with the purpose of meeting the timetables published by shipping liners, and (ii) the minimization of the total yard transportation distance with the aim to lower terminal operational cost. We propose a bi-objective integer program which can comprehensively address the import, export and transshipment tasks in port daily practice. Traditionally, a container transshipment task is performed as a couple of import and export tasks, called indirect-transshipment mode, in which the transit container are needed to be temporally stored in the yard. As the way of transferring containers directly from the incoming vessel to the outgoing vessel, called direct-transshipment mode, has potential to save yard storage resources, the proposed model also incorporates both indirect- and direct-transshipment modes. To produce Pareto solutions efficiently, we devise heuristic approaches. Numerical experiments have been conducted to demonstrate the efficiency of the approaches.     

A ‘Less-flexibility-first’ Heuristic for the Placement of Inland Vessels in a Lock

Abstract

Inland vessels move goods along waterways (canals and rivers) and they visit ports. Because of their tidal nature, vessels make use of locks to enter ports or waterways. From a port management point of view, fast access to and from the port and high utilization of locks are important objectives. Where the former relates to low inbound and outbound waiting times, the latter relates to the placement of as many vessels as possible in the lock before its operation. This article includes a case study that relates to the operation of the Van Cauwelaert lock in the port of Antwerp, Belgium. Lock operation policy is as follows: vessels wait in front of the lock for a port administrator to assign places in the lock based on knowledge of the vessels’ dimensions. As such, there is no FIFO-discipline, but a ‘group-FIFO’-discipline, i.e. if n vessels are allowed into the lock, they are the first n vessels in the arrival queue. A heuristic algorithm is formulated for the placement of vessels in the lock. This algorithm supports the decision where to place the vessel in the lock, aiming to place as many vessels as possible from the arrival queue. At the same time, it supports the decision to start a locking operation or not, based on information about vessels that are announced but which have not yet arrived at the lock's entrance. The heuristic is called a ‘less-flexibility-first’-heuristic as it looks for pseudo-placements, showing which flexibility is left for the remaining vessels after placing a vessel. This article describes the implementation of the heuristic and provides numerical examples. A comparison is made between the heuristic results and daily practice, based on real-life vessel movements through the Van Cauwelaert lock in 2002.     

Integrated modeling of information and physical flows in transportation systems

Modeling transportation systems operations in large part involves an understanding of how physical entities (i.e., vehicles) move and interact with each other in the system. Transportation systems that are integrated with information technologies involve flow of information besides the flow of physical entities. In some cases, a unified modeling approach that considers both flows is needed to create an accurate model for system operations. This paper highlights the significance of such a modeling approach that involves an explicit representation of information flow attributes (e.g., response time and information delay). Several small-scale queuing models are developed to illustrate the importance of incorporating information flow related attributes into the models of transportation systems operations. In each example system, two scenarios are considered: modeling the given system with or without explicitly representing the information flow. Comparison of performance statistics is made between these two scenarios. It is found that ignoring information flows may lead to significant inaccuracies in the estimates of the system performance.     

A congested and dwell time dependent transit corridor assignment model

This research proposes an equilibrium assignment model for congested public transport corridors in urban areas. In this model, journey times incorporate the effect of bus queuing on travel times and boarding and alighting passengers on dwell times at stops. The model also considers limited bus capacity leading to longer waiting times and more uncomfortable journeys. The proposed model is applied to an example network, and the results are compared with those obtained in a recent study. This is followed by the analysis and discussion of a real case application in Santiago de Chile. Finally, different boarding and alighting times and different vehicle types are evaluated. In all cases, demand on express services tends to be underestimated by using constant dwell time assignment models, leading to potential planning errors for these lines. The results demonstrate the importance of considering demand dependent dwell times in the assignment process, especially at high demand levels when the capacity constraint should also be considered. Copyright © 2017 John Wiley & Sons, Ltd.     

Robust supply vessel routing and scheduling

We solve the problem of tactical supply vessel planning arising in the upstream offshore petroleum logistics. Supply vessels deliver all the necessary materials and equipment to offshore installations from an onshore supply base according to a delivery schedule. The planning of supply vessels should be done so that their number is minimized and at the same time provide a reliable flow of supplies from the base. The execution of a weekly sailing plan is affected by weather conditions, especially in winter time. Harsh weather conditions increase the number of vessels required to perform the operations as well as the service times at the installations, and thus disrupt the schedule, leading to additional costs and reduced service level. We present a methodology for robust supply vessel planning enabling a trade-off analysis to be made between the schedules’ service level and vessels’ cost. The methodology involves the generation of multiple vessel schedules with different level of robustness using an adaptive large neighbourhood search metaheuristic and a subsequent discrete event simulation procedure for the assessment of the service level. To control the level of robustness we developed a concept of slacks and incorporated it into the metaheuristic algorithm.     

Evaluation of the dry port concept from an environmental perspective: A note

This study evaluates the dry port concept from an environmental perspective using modelling and simulation. A model of a transport system, with and without a dry port, is created and the results of the simulations compared. The benefits of the dry port implementation are defined from an environmental perspective; calculated CO₂ emissions are approximately 25% lower with an implemented dry port for the chosen case, while congestion and truck waiting times at the terminal are significantly reduced.     

The Greening of Ports: A Comparison of Port Management Tools Used by Leading Ports in Asia and Europe

Abstract

From the policy and management perspective, this study aims to investigate the port management tools that port/public authorities have at their disposal and then to analyse to what extent the tools are used to enforce or encourage green port development at functional activities of port operations and development. We conduct an exploratory and comparative review based on two axes: on the one hand, the range of tools available to port authorities (pricing, monitoring and measuring, market access control and environmental standard regulation) and on the other hand, the functional activities in ports (shipping traffic, cargo handling and storage operations, intermodal connection, industrial activities, and port expansion). The situations in the leading ports in Asia and Europe, namely Singapore, Shanghai, Antwerp and Rotterdam are studied and compared, whereby the policies' effectiveness is discussed accordingly. Findings show that the ports are particularly mature in exercising environmental standard regulations which reveals that the enforcement approach is more prevalent. The most focused functional activity is shipping traffic which reflects that the ports are driven by the International Maritime Organisation. The respective port authorities in Antwerp and Rotterdam have a higher level of influence on devising green port policy in comparison to the two Asian ports.     

The status of German railway operations management in research and practice

The German railway operations management uses probabilistic and simulation methods in research and practice. The probabilistic methods are based on queuing theory. There are synchronous or asynchronous algorithms for the simulation of time tables, schedule, operation, and disposition. Models were also developed for the simulation of the operation in many parts of the network for the connection between the structure of the track and the capacity of lines and stations, for the evaluation of operating cost depending from the quality of service, and for the design of integrated timetables.