5,610 research outputs found

    An Improved Fuzzy Knowledge-Based Model For Long Stay Container Yards

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    This paper considers the problem of allocating newly arrived containers to stacks of existing containers in a yard when the departure date/time for containers is unknown. Many factors and constraints need to be considered when modelling this storage allocation problem. These constraints include the size, type and weight of the containers. The factors are the number of containers in a stack and the duration of stay of the topmost container in the stack. This paper aims to develop an improved Fuzzy Knowledge-Based ‘FKB’ model for best allocation practice of long-stay containers in a yard. In this model, the duration of stay factor does not need to be considered in the allocation decision if the duration of stay for the topmost containers in a stack is similar; hence, a new ‘ON/OFF’ strategy is proposed within the Fuzzy Knowledge-Based model to activate/deactivate this factor in the stacking algorithm whenever is required. Discrete Event Simulation and Fuzzy Knowledge-Based techniques are used to develop the proposed model. The model’s behaviour is tested using three real-life scenarios, including allocating containers in busy, moderately busy and quiet yards. The total number of re-handlings, the number of re-handlings per stack, and the number of re-handlings for containers were considered KPIs in each scenario

    Automated biowaste sampling system urine subsystem operating model, part 1

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    The urine subsystem automatically provides for the collection, volume sensing, and sampling of urine from six subjects during space flight. Verification of the subsystem design was a primary objective of the current effort which was accomplished thru the detail design, fabrication, and verification testing of an operating model of the subsystem

    Optimal Planning of Container Terminal Operations

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    Due to globalization and international trade, moving goods using a mixture of transportation modes has become a norm; today, large vessels transport 95% of the international cargos. In the first part of this thesis, the emphasis is on the sea-land intermodal transport. The availability of different modes of transportation (rail/road/direct) in sea-land intermodal transport and container flows (import, export, transhipment) through the terminal are considered simultaneously within a given planning time horizon. We have also formulated this problem as an Integer Programming (IP) model and the objective is to minimise storage cost, loading and transportation cost from/to the customers. To further understand the computational complexity and performance of the model, we have randomly generated a large number of test instances for extensive experimentation of the algorithm. Since, CPLEX was unable to find the optimal solution for the large test problems; a heuristic algorithm has been devised based on the original IP model to find near „optimal‟ solutions with a relative error of less than 4%. Furthermore, we developed and implemented Lagrangian Relaxation (LR) of the IP formulation of the original problem. The bounds derived from LR were improved using sub-gradient optimisation and computational results are presented. In the second part of the thesis, we consider the combined problems of container assignment and yard crane (YC) deployment within the container terminal. A new IP formulation has been developed using a unified approach with the view to determining optimal container flows and YC requirements within a given planning time horizon. We designed a Branch and Cut (B&C) algorithm to solve the problem to optimality which was computationally evaluated. A novel heuristic approach based on the IP formulation was developed and implemented in C++. Detailed computational results are reported for both the exact and heuristic algorithms using a large number of randomly generated test problems. A practical application of the proposed model in the context of a real case-study is also presented. Finally, a simulation model of container terminal operations based on discrete-event simulation has been developed and implemented with the view of validating the above optimisation model and using it as a test bed for evaluating different operational scenarios

    A System Based on Fuzzy Logic to Manage Operations in Container Yards

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    This article focuses on the assignment of arrived containers to pre-existing stacks stored in one of the container yards, particularly when the containers' date of departure and time are unknown. This becomes more difficult when different-sized, typed, and weighted containers needs be stored in pre-existing containers yard. The main objective is to create a Fuzzy Knowledge-Based System (FKB_CYM) that considers practical factors and limitations such as container quantity per stack and customer, type, size, and weight. Various tools and methodologies are used, including Discrete Event (DE), Fuzzy Knowledge-Based Modelling (FKBM), and a Neighborhood Algorithm (NA). The paper thoroughly discusses and evaluates the system's findings

    Space-sharing Strategies for Storage Yard Management in a Transshipment Hub Port

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    Ph.DDOCTOR OF PHILOSOPH

    Uncertainty and the Value of Information in Hinterland Transport Planning

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    Hester Gardens - A LifeMoves Temporary Interim-Housing Facility

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    LifeMoves, an organization that provides interim housing and supportive services to families and individuals experiencing homelessness, recently purchased 0.35 acres of land, located at 1759 Hester Avenue, San Jose, CA 95128. LifeMoves has challenged the design team to provide preliminary building layouts, a structural alternative analysis, construction management plans, and general civil plans for a multi-story, family-friendly, interim housing facility, which has been named Hester Gardens. The design team considered both steel, a traditional building material, and shipping containers, a sustainable alternative building material, for this project. Each alternative included a structural design and analysis, as well as a cost estimate and construction schedule. A conceptual plan, site and building layout, utility plan, necessary mock permits, and a recommended alternative plan was drawn for LifeMoves. The finished design documents, models, and printed plan drawings were turned over to LifeMoves
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