Integrated maritime fleet deployment and speed optimization: Case study from RoRo shipping

2015 ◽  
Vol 55 ◽  
pp. 233-240 ◽  
Author(s):  
Henrik Andersson ◽  
Kjetil Fagerholt ◽  
Kirsti Hobbesland
Keyword(s):  
Speed Optimization ◽  
Fleet Deployment

Adapting Procurement Models for Electric Buses in Latin America

2019 ◽  
Vol 2673 (10) ◽  
pp. 175-184
Author(s):  
Jone Orbea ◽  
Sebastian Castellanos ◽  
Cristina Albuquerque ◽  
Ryan Sclar ◽  
Berta Pinheiro
Keyword(s):  
Latin America ◽  
Case Study Research ◽  
Transit System ◽  
Charging Infrastructure ◽  
Proposed Model ◽  
Bus Service ◽  
Bus Services ◽  
Fleet Deployment

Bus services are a fundamental component of transportation networks in Latin America, but buses often account for a disproportionately large number of environmental externalities. Electric buses (e-buses) are emerging as an effective and pragmatic option for reducing greenhouse gas emissions and local pollutants. However, e-buses are difficult to procure in Latin America because of existing procurement challenges in the region, especially as those challenges relate to forming contracts to deal with high upfront costs and unknown risks. To overcome these procurement issues, this paper presents a new contractual model, based on literature and case study research. This new model suggests the separation of bus service responsibilities into three separate actors: multiple bus procurement companies, one or multiple bus depots and charging infrastructure companies, and multiple bus operating companies. By separating bus service responsibilities, the proposed model would bring about three concrete improvements: lower costs to the transit system, better quality of service, and lower-emission fleet deployment.

Fleet deployment in liner shipping: a case study

2009 ◽  
Vol 36 (5) ◽  
pp. 397-409 ◽  
Author(s):  
Kjetil Fagerholt ◽  
Trond A. V. Johnsen ◽  
Haakon Lindstad
Keyword(s):  
Liner Shipping ◽  
Fleet Deployment

Joint Planning of Fleet Deployment, Speed Optimization, and Cargo Allocation for Liner Shipping

2015 ◽  
Vol 49 (4) ◽  
pp. 922-938 ◽  
Author(s):  
Jun Xia ◽  
Kevin X. Li ◽  
Hong Ma ◽  
Zhou Xu
Keyword(s):  
Liner Shipping ◽  
Speed Optimization ◽  
Joint Planning ◽  
Fleet Deployment

scholarly journals A Holistic Optimization Model for Integrated Tactical Level Planning in Liner Shipping

2020 ◽  
Author(s):  
Junayed Pasha
Keyword(s):  
Mathematical Model ◽  
Liner Shipping ◽  
Operational Cost ◽  
Inventory Cost ◽  
Frequency Determination ◽  
Vessel Scheduling ◽  
Late Arrival ◽  
Speed Optimization ◽  
Service Frequency ◽  
Fleet Deployment

Supply chain management plays an important role in ensuring an efficient merchandise trade. Freight transportation is an integral part of supply chain management. A significant part of freight transportation is covered by maritime transportation, as the largest portion of the global merchandise trade, in terms of volume, is carried out by maritime transportation. Liner shipping, which runs on fixed routes and schedules, plays a colossal role for the global seaborne trade. Liner shipping companies deal with three decision levels, namely strategic level, tactical level, and operational level. The strategic-level decisions are taken for more than six months to several years. The tactical-level decisions are effective for three months to six months. Moreover, the operational level decisions are taken for a couple of weeks to less than three months.This dissertation involves the tactical-level decisions in liner shipping, which include: (1) service frequency determination; (2) fleet deployment; (3) sailing speed optimization; and (4) vessel scheduling. The service frequency determination problem deals with determining the time headway between consecutive vessels along a liner shipping route. The fleet deployment problem assigns vessels from the liner shipping company’s fleet (and sometimes, from other liner shipping companies’ fleets) to liner shipping routes. The sailing speed optimization problem deals with selecting sailing speeds along different voyage legs of a given port rotation. The vessel scheduling problem lists the schedules (e.g., arrival time, handling time, departure time) at different ports.A comprehensive review of the liner shipping literature revealed that the existing literature on the tactical-level decisions focused on these problems individually. Solutions from different solution methodologies for the separate problems may have compatibility problems. Moreover, they are not attractive to the liner shipping companies, who look for integrated solutions. Hence, this research aimed to develop a combined mathematical model that comprises the four tactical-level decisions in liner shipping (i.e., service frequency determination, fleet deployment, sailing speed optimization, and vessel scheduling). This mathematical model is named the Holistic Optimization Model for Tactical-Level Planning in Liner Shipping (HOMTLP).The objective of the HOMTLP mathematical model is to maximize of the total profit from transport of cargo. The major route service cost components, found from the literature, are covered by the model, which include: (I) total late arrival cost; (II) total port handling cost; (III) total fuel consumption cost; (IV) total vessel operational cost; (V) total vessel chartering cost; (VI) total container inventory cost in sea; (VII) total container inventory cost at ports of call; (VIII) total emission cost in sea; and (IX) total emission cost at ports of call. Along with the integration of all four tactical-level decisions, the mathematical model has a number of key advantages. First, the model provides flexibility to both the liner shipping company and the marine container terminal operators, as it offers multiple time windows and handling rates at each port of call. Second, the payload carried by the vessels is considered while estimating fuel consumption. Third, the preference of customers is reflected by modification of the container demand at different sailing speeds. Fourth, container inventory is accounted for at ports of call and in sea. Fifth, emissions of different harmful substances are captured in order to preserve the environment.This dissertation carried out a set of numerical experiments to test the performance of the HOMTLP model, where BARON was used as the solution approach. It was revealed that when there was an increase in the unit fuel cost, the unit emission cost, vessel availability, the unit late arrival cost, and the unit freight rate, the sailing speed was reduced. On the other hand, when there was an increase in the unit inventory cost, the unit operational cost, as well as the unit chartering cost, the sailing speed was increased. Moreover, the total required number of vessels was increased, when there as an increase in the unit fuel cost, the unit emission cost, vessel availability, the unit late arrival cost, and the unit freight rate. On the contrary, the total required number of vessels was decreased, when there was an increase in the unit inventory cost, the unit operational cost as well as the unit chartering cost. It was also revealed that the total profit was increased, when more choices were available for time windows and/or container handling rates. The numerical experiments highlighted several other findings. Most importantly, it was found that the HOMTLP model can provide effective tactical-level decisions. Hence, the mathematical model can assist liner shipping companies to take tactical-level decisions, which are effective and profitable.

scholarly journals Speed Optimization for Container Ship Fleet Deployment Considering Fuel Consumption

2021 ◽  
Vol 13 (9) ◽  
pp. 5242
Author(s):  
Chao-Feng Gao ◽  
Zhi-Hua Hu
Keyword(s):  
Energy Consumption ◽  
Approximation Algorithm ◽  
Fuel Consumption ◽  
Programming Model ◽  
Mixed Integer ◽  
Piecewise Linear Approximation ◽  
Container Ship ◽  
Trade Offs ◽  
Speed Optimization ◽  
Fleet Deployment

In recent years, low energy consumption has become the common choice of economic development in the world. In order to control energy consumption, shipping line speed optimization has become strategically important. to reduce fuel consumption, this study optimizes the container ship fleet deployment problem by adopting the strategy of adjusting each leg of each route’s sailing speed. To calculate fuel consumption more accurately, both sailing speed and the ship's payload are considered. A multi-objective mixed integer nonlinear programming model is established to optimize the allocation of liner routes with multiple ship types on multiple routes. A linear outer-approximation algorithm and an improved piecewise linear approximation algorithm are used for linearization. If segments of an interval increase, the results will be more accurate but will take more time to compute. As fuel prices increase, to make trade-offs among economic and environmental considerations, the shipping company is adopting the “adding ship and slow down its speed” strategy, which verifies the validity and applicability of the established model.

Liner Shipping Service Planning Under Sulfur Emission Regulations

2020 ◽  
Author(s):  
Shuaian Wang ◽  
Dan Zhuge ◽  
Lu Zhen ◽  
Chung-Yee Lee
Keyword(s):  
Operations Management ◽  
Operating Cost ◽  
Liner Shipping ◽  
Service Planning ◽  
Planning Problem ◽  
Marine Fuel ◽  
Speed Optimization ◽  
Schedule Design ◽  
Low Sulfur ◽  
Fleet Deployment

Air emissions from ships have become an important issue in sustainable shipping because of the low quality of the marine fuel consumed by ships. To reduce sulfur emissions from shipping, the International Maritime Organization has established emission control areas (ECAs) where ships must use low-sulfur fuel with at most 0.1% sulfur or take equivalent emission-reduction measures. The use of low-sulfur fuel increases the costs for liner shipping companies and affects their operations management. This study addresses a holistic liner shipping service planning problem that integrates fleet deployment, schedule design, and sailing path and speed optimization, considering the effect of ECAs. We propose a nesting algorithmic framework to address this new and challenging problem. Semianalytical solutions are derived for the sailing path and speed optimization problem, which are used in the schedule design. A tailored algorithm is applied to solve schedule design problems, and the solutions are used in fleet deployment. The fleet deployment problem is then addressed by a dynamic programming-based pseudo-polynomial time algorithm. Numerical experiments demonstrate that considering the effect of ECAs in liner shipping operations management can reduce over 2% of the costs, which is significant considering that the annual operating cost of a shipping company’s network can be as high as several billion dollars.

scholarly journals Maritime Fleet Deployment with Speed Optimization and Voyage Separation Requirements

2018 ◽  
pp. 32-46
Author(s):  
Venke Borander ◽  
Anders Straume ◽  
Bo Dong ◽  
Kjetil Fagerholt ◽  
Xin Wang
Keyword(s):  
Speed Optimization ◽  
Fleet Deployment

The Genesis and Internal Dynamics of El Salvador's People's Revolutionary Army, 1970–1976

2014 ◽  
Vol 38 (01) ◽  
pp. 102-129
Author(s):  
ALBERTO MARTÍN ÁLVAREZ ◽  
EUDALD CORTINA ORERO
Keyword(s):  
Latin America ◽  
El Salvador ◽  
Early Years ◽  
Left Wing ◽  
Internal Dynamics ◽  
Internal Coherence ◽  
The 1960S

AbstractUsing interviews with former militants and previously unpublished documents, this article traces the genesis and internal dynamics of the Ejército Revolucionario del Pueblo (People's Revolutionary Army, ERP) in El Salvador during the early years of its existence (1970–6). This period was marked by the inability of the ERP to maintain internal coherence or any consensus on revolutionary strategy, which led to a series of splits and internal fights over control of the organisation. The evidence marshalled in this case study sheds new light on the origins of the armed Salvadorean Left and thus contributes to a wider understanding of the processes of formation and internal dynamics of armed left-wing groups that emerged from the 1960s onwards in Latin America.

Culture and the plasticity of perception

2020 ◽  
Vol 43 ◽  
Author(s):  
Michael Lifshitz ◽  
T. M. Luhrmann
Keyword(s):  
Cultural Context ◽  
Sensory Experience ◽  
Cultural Learning ◽  
The World

Abstract Culture shapes our basic sensory experience of the world. This is particularly striking in the study of religion and psychosis, where we and others have shown that cultural context determines both the structure and content of hallucination-like events. The cultural shaping of hallucinations may provide a rich case-study for linking cultural learning with emerging prediction-based models of perception.

Sign in / Sign up

Export Citation Format

Share Document