294 research outputs found

    Speed optimization and bunkering in liner shipping in the presence of uncertain service times and time windows at ports

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    © 2016 The Authors. Recent studies in maritime shipping have concentrated on environmental and economic impacts of ships. In this regard, fuel is considered as one of the important factors for such impacts. In particular, the sailing speed of the vessels affects the fuel consumption directly. In this study, we consider a speed optimization problem in liner shipping, which is characterized by stochastic port times and time windows. The objective is to minimize the total fuel consumption while maintaining the schedule reliability. We develop a dynamic programming model by discretizing the port arrival times to provide approximate solutions. A deterministic model is presented to provide a lower bound on the optimal expected cost of the dynamic model. We also work on the effect of bunker prices on the liner service schedule. We propose a dynamic programming model for bunkering problem. Our numerical study using real data from a European liner shipping company indicates that the speed policy obtained by proposed dynamic model performs signi cantly better than the ones obtained by benchmark methods. Moreover, our results show that making speed decisions considering the uncertainty of port times will noticeably decrease fuel consumption cost.This research is supported in part by EU FP7 project MINI-CHIP (Minimising Carbon Footprint in Maritime Shipping) under grant number PIAP-GA-2013-611693

    Collaborative relationships between logistics service providers and humanitarian organizations during disaster relief operations

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    Purpose: this study explores barriers and benefits of establishing relationships between humanitarian organizations (HOs) and logistics service providers (LSPs) in order to improve humanitarian disaster relief operations (DROs). the perceptions of a variety of actors are explored to determine key factors which influence collaboration. Design/ methodology/ approach: This study comprises of quantitative methodological approaches. a comprehensive literature review was undertaken alongside an online survey with a variety of respondents. descriptive statistics, data visualization and qualitative data analysis were implemented to analyse survey results. a follow-up survey and interviews with LSPs validated the results. Findings, the research presents the opinions of a variety of actors involved in DROs and reveals barriers which affect HO/LSP collaboration. explanations for these barriers and possible solutions to mitigate them are disclosed. the findings also uncover gaps between research and practice; providing new insights into behaviour in the humanitarian field. Practical implications: We provide an in-depth understanding of the barriers and challenges faced in this field and suggest a revaluation of corporate decision making in order to increase trust between LSPs and HOs. We identify future research topics including the impact of donors and military organisations on HO decision making, and analysis of variables which may affect the formation of collaborative partnerships. Originality/value: We introduce a unique empirical insight into the perspective of HOs, LSPs and academics and offers suggestions for mitigating the numerous barriers associated with successful collaborative partnerships between HOs and LSPs

    Integrated business continuity and disaster recovery planning: Towards organizational resilience

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    Businesses are increasingly subject to disruptions. It is almost impossible to predict their nature, time and extent. Therefore, organizations need a proactive approach equipped with a decision support framework to protect themselves against the outcomes of disruptive events. In this paper, a novel framework is proposed for Integrated Business Continuity and Disaster Recovery Planning for efficient and effective resuming and recovering of critical operations after being disrupted. The proposed model addresses decision problems at all strategic, tactical and operational levels. At the strategic level, the context of the organization is first explored and the main features of the organizational resiliency are recognized. Then, a new multi-objective mixed integer linear programming model is formulated to allocate internal and external resources to both resuming and recovery plans simultaneously. The model aims to control the loss of resiliency by maximizing recovery point and minimizing recovery time objectives. Finally, at the operational level, hypothetical disruptive events are examined to evaluate the applicability of the plans. We also develop a novel interactive augmented ε-constraint method to find the final preferred compromise solution. The proposed model and solution method are finally validated through a real case study

    The lean-performance relationship in services: A theoretical model

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    A successful software project is the result of a complex process involving, above all, people. Developers are the key factors for the success of a software development process, not merely as executors of tasks, but as protagonists and core of the whole development process. This paper investigates social aspects among developers working on software projects developed with the support of Agile tools. We studied 22 open-source software projects developed using the Agile board of the JIRA repository. All comments committed by developers involved in the projects were analyzed and we explored whether the politeness of comments affected the number of developers involved and the time required to fix any given issue. Our results showed that the level of politeness in the communication process among developers does have an effect on the time required to fix issues and, in the majority of the analysed projects, it had a positive correlation with attractiveness of the project to both active and potential developers. The more polite developers were, the less time it took to fix an issue.UK Engineering and Physical Sciences Research Counci