Modeling the mixed storage strategy for quay crane double cycling in container terminals

A mixed storage strategy was proposed to improve the efficiency of yard operations and horizontal transportation to corporate with quay crane double cycling. The effects of the mixed storage strategy on terminal operations, including truck travel distance, yard crane operations and the number of required trucks, were analyzed. An approach based on cycle-time models, the queuing theory was proposed to evaluate the performances from long-term run. Results show using the mixed storage strategy, the truck travel distance can be decreased and the number of required trucks and yard crane’s operation time can be reduced by 16% and 26% respectively.     

Joint planning of berth and yard allocation in transshipment terminals using multi-cluster stacking strategy

In this work, a joint planning problem for berth and yard allocation in transshipment terminals is addressed. Multi-cluster stacking strategy is proposed to split each transshipment flow into a number of container clusters and then stack each cluster in different yard blocks. A mixed integer quadratic programming model is formulated to minimize the total distance of exchanging containers between mother vessels and feeders, and the workload imbalance among yard blocks. A novel three-stage heuristic solution approach is developed and extensive numerical experiments are conducted to show the effectiveness of the proposed approach and the benefit of the multi-cluster strategy.     

Terminal and yard allocation problem for a container transshipment hub with multiple terminals

This paper presents an integer programming model for the terminal and yard allocation problem in a large container transshipment hub with multiple terminals. The model integrates two decisions: terminal allocation for vessels and yard allocation for transshipment container movements within a terminal as well as between terminals. The objective function aims to minimize the total inter-terminal and intra-terminal handling costs generated by transshipment flows. To solve the problem, we develop a 2-level heuristic algorithm to obtain high quality solutions in an efficient way. Computational experiments show the effectiveness of the proposed approach.     

Space allocating strategies for improving import yard performance at marine terminals

This paper focuses on the organization of the import storage yard at container port terminals. Three new stacking strategies are introduced which take into account the containers’ arrival and departure rates and the storage yard characteristics. A mathematical model based on probabilistic distribution functions is developed to estimate the number of rehandles required to manage an import container yard. The model is applied to the three proposed stacking strategies. Results show that the optimal strategy depends on stacking height and the relationship between vessel headway and container dwell time.     

Tactical berth and yard template design at container transshipment terminals: A column generation based approach

Quay-side berthing congestion is an emerging challenging issue that arises in busy container transshipment terminals and calls for effective management of terminal operations. This paper tackles the berthing congestion problem by introducing a proactive management strategy from the terminal’s perspective that adjusts the calling schedule of feeder vessels in such a way that the quay-side workload distribution in the temporal dimension can be balanced. Such a schedule template design problem is considered simultaneously with another two tactical level decision problems, berth template design (i.e., determining preferred berthing positions for vessels) and yard template design (i.e., allocating storage yard space to transshipment flows). This highly integrated problem is formulated as a set covering model. Heuristic methods based on column generation are developed to obtain near-optimal solutions in an efficient way. Computational experiments on real-world sized test instances demonstrate the efficiency and effectiveness of the proposed approach.     

Reducing truck emissions at container terminals in a low carbon economy: Proposal of a queueing-based bi-objective model for optimizing truck arrival pattern

This study proposes a methodology to optimize truck arrival patterns to reduce emissions from idling truck engines at marine container terminals. A bi-objective model is developed minimizing both truck waiting times and truck arrival pattern change. The truck waiting time is estimated via a queueing network. Based on the waiting time, truck idling emissions are estimated. The proposed methodology is evaluated with a case study, where truck arrival rates vary over time. We propose a Genetic Algorithm based heuristic to solve the resulting problem. Result shows that, a small shift of truck arrivals can significantly reduce truck emissions, especially at the gate.     

Analysis of factors underlying foreign entry strategies of terminal operators in container ports

Port reforms around the world have opened regional container port terminal markets. The emergence of a wide array of global terminal operators has led to a differentiation in entry strategies driven by their respective objectives and by factors exogenous to the firm.This paper looks at antecedent factors that play a role in a company’s entry strategy in a public–private partnership (PPP) setting by performing binomial logistic regression on a large sample of container terminal deals over the period 2002–2010. More specifically, it analyses to what extent firm-specific, external, project and cross-cultural factors play a decisive role in the choice between direct PPPs (i.e. stepping into a new PPP arrangement such as a new concession agreement) and indirect PPPs (i.e. stepping into an existing PPP arrangement through acquisitions).The empirical findings demonstrate the pivotal role of some firm specific characteristics (market experience and business model), external factors (host country development and market openness, government effectiveness, market concentration degree, and market saturation) and project-related factors (project size, number of partners involved, and equity joint venture with the Port Authority), also unveiling some preliminary results in relation to cross-cultural variables.     

Levels of internationalization in the container shipping industry: an assessment of the port networks of the large container shipping companies

This paper examines the internationalization level of the world’s largest container shipping companies by examining their port networks. The results of our analysis show that only three of the nineteen companies could be considered as being truly ‘International’ and service the ‘lion’s share’ of the major and minor ports distributed across the globe. The port networks of the other companies in our survey, whilst having individualized features, shared common characteristics. Guided by the ‘Uppsala Model of Incremental Internationalization’ (Johanson and Vahlne, 1977), we were able to identify four internationalization levels of a container shipping company that are indicated by their port network.We argue that the port network plays an additional role as it contributes to the internationalization level of the container shipping companies. This is important because the internationalization level affects the container shipping company’s ability to expand its customer base both at a local and international level. Local customers would have access to a larger international destination network and international customers would be able access a larger local distribution network without transhipping between different companies.Amongst other issues, we were able to determine that, for the analyzed container shipping companies, ‘Internationalization’ of a port network means including or excluding ports in specific regions or sub-regions in their own network, and that a company’s home base or history plays a significant role in this development.     

Sailing speed optimization for container ships in a liner shipping network

This paper first calibrates the bunker consumption - sailing speed relation for container ships using historical operating data from a global liner shipping company. It proceeds to investigate the optimal sailing speed of container ships on each leg of each ship route in a liner shipping network while considering transshipment and container routing. This problem is formulated as a mixed-integer nonlinear programming model. In view of the convexity, non-negativity, and univariate properties of the bunker consumption function, an efficient outer-approximation method is proposed to obtain an ε-optimal solution with a predetermined optimality tolerance level ε. The proposed model and algorithm is applied to a real case study for a global liner shipping company.     

The Self-Learning Particle Swarm Optimization approach for routing pickup and delivery of multiple products with material handling in multiple cross-docks

Vehicle Routing Problems (VRPs) in distribution centers with cross-docking operations are more complex than the traditional ones. This paper attempts to address the VRP of distribution centers with multiple cross-docks for processing multiple products. In this paper, the mathematical model intends to minimize the total cost of operations subjected to a set of constraints. Due to high complexity of model, it is solved by using a variant of Particle Swarm Optimization (PSO) with a Self-Learning strategy, namely SLPSO. To validate the effectiveness of SLPSO approach, benchmark problems in the literature and test problems are solved by SLPSO.     

A heuristic algorithm for yard truck scheduling and storage allocation problems

The yard truck scheduling and the storage allocation are two important decision problems affecting the efficiency of container terminal operations. This paper proposes a novel approach that integrates these two problems into a whole. The objective is to minimize the weighted sum of total delay of requests and the total travel time of yard trucks. Due to the intractability of the proposed problem, a hybrid insertion algorithm is designed for effective problem solutions. Computational experiments are conducted to examine the key factors of the problem and the performance of the proposed heuristic algorithm.     

Inventory optimization for a customer airline in a Performance Based Contract

The supply of spare parts has a crucial role in the aviation sector, mainly due to the high costs of spare parts and to the strict availability requirements. In a stand-alone scenario, an airline owns the spare parts and manages the maintenance tasks by itself. A new trend consists of not owning the spare parts and delegate the maintenance tasks to an external company, taking advantage of a specific Performance Based Contract (PBC). The PBCs aim to reduce the ownership cost for the customer airline, while ensuring a target system performance. Spare parts become a variable cost for the customer airline and a business income for the maintenance supplier, which is commonly another airline.This paper proposes an innovative model, i.e. the PBC-METRIC, which supports the customer airline manager to minimize the spare parts supply cost, in compliance with the airline availability requirements and with respect to the PBC. In detail, the PBC-METRIC models a multi-echelon, multi-item, single-indenture, multi-transportation network, by an innovative two-steps algorithm, defining the PBC specifications as modelling variables and parameters. A case study on a European airline, with the role of customer in a PBC, illustrates the outcome of the model.     

The optimization model for the location of maritime emergency supplies reserve bases and the configuration of salvage vessels

This paper studies the location–allocation–configuration problem of emergency resources in a maritime emergency system and it proposes a discrete nonlinear integer-programming model, which integrates the location, allocation and the configuration problem. The model is converted into a two-stage model keeping the calculation logic. It designs a hybrid heuristic algorithm and a genetic algorithm. The test results show that the hybrid heuristic algorithm is more efficient than the genetic algorithm, the sensitivity analysis studies the influence of some parameters to the final solution and the Uncertainty–Sensitivity justification tool is used to evaluate the assumptions.     

在国家现代综合交通运输体系建设中确立铁路优先发展战略

分析铁路运输能力远远不能满足国民经济发展需求的原因,系统阐述在国家现代综合交通运输体系建设中确立铁路优先发展战略的重要性、紧迫性,提出国家优先发展铁路的建议。     

Comparison of solution approaches for the train load planning problem in seaport terminals

In this paper the train load planning problem arising in a seaport container terminal is considered. This problem consists in determining the optimal assignment of containers to wagon slots in order to maximize the train utilization and, at the same time, to minimize unproductive operations in the terminal. Different solution approaches based on a mathematical programming model are compared. The best solution procedure, satisfactory both in terms of quality of the obtained solutions and for the computational times, is identified through extensive experimental tests. This procedure could be included in a planning tool to be used in real seaport terminals.     

基于滚动时域优化的高速铁路车站到发线动态调整研究

高速铁路车站到发线动态调整是调度指挥工作的重点之一,具有复杂多变、实时性强的特点,亟需实现到发线调整的自动化和智能化。阐述高速铁路车站到发线动态调整问题本质,引入滚动时域调度策略,建立高速铁路车站到发线动态调整模型。该模型为以列车晚点总时长最小为目标的0-1整数规划模型,采用遗传算法求解。以某高速铁路车站为例,根据列车运行图中列车到发时刻和晚点信息进行计算。研究结果表明:该模型可以有效提高到发线调整的实时性,保障列车在车站内稳定运行,为高速铁路车站智能调度提供了研究支持。     

The joint replenishment and delivery scheduling of the one-warehouse, n-retailer system

We deal with the joint replenishment and delivery scheduling of the one-warehouse, n-retailer system in this paper. We suggest a more flexible policy for the joint replenishment and delivery scheduling of a warehouse compared with the existing researches. We introduce the mathematical model and two efficient algorithms for the joint replenishment and delivery scheduling of the warehouse. Subsequently, we develop the hybrid genetic algorithm (GA) and compare it with two efficient heuristic algorithms for extensive computational experiments. Further, we show the advantages of our GA in dealing easily with resource restrictions.     

贯彻实施"一主两翼"运输战略深入开展华东二通道安全优质高效文明达标线创建活动

分析开展华东二通道安全优质高效文明达标线创建的意义,结合二通道设备、管理等方面存在的问题,探讨如何推进华东二通道创建工作.     

The effect of a destination branding strategy for rural tourism on the perceived value of the conservation of the indigenous resources of the rural tourism destination: the case of Spain

The identification of mechanisms that encourage the tourism sector to contribute to sustainable conservation is of great interest. The present work proposes the use of destination branding based on contribution to the conservation of the indigenous resources of the rural tourist destination, and studies the effect this has on perceived value for the tourist visiting the destination. A scale of destination brand identity is validated, along with a scale for destination brand positioning and another for perceived value, as viewed by the tourist, of contribution to sustainable conservation. The perceived value scale offers an overall perspective which includes: functional-affective factors; benefits–sacrifices; the pre-visit stage; and the stay in the rural tourism location. These findings make a new contribution to both literature and to the professional sector.     

双线铁路列车调度阶段计划自动调整的遗传算法

列车运行调整是一类NP完全问题,在借鉴国内外专家对铁路列车运行自动调整研究成果的基础上,建立双线铁路列车调度阶段计划自动调整数学模型,并给出相关约束表达式。根据遗传算法原理,对阶段计划自动调整模型进行优化,采用罚函数法对约束条件进行处理,建立基于惩罚函数的适应度函数,采用交叉、变异等技术给出遗传算法的基本求解步骤。