6 research outputs found

    Projects Never Fail: A Critical Review on Estimation of Project Scheduling and Project Costing

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    Uncertainty remains common in all projects. It is need to realize this uncertainty and have to minimize the effect of this uncertainty to achieve better project outcomes. To realize the project on truthful base it is required to develop project schedule and estimate project costing on reality bases. A lot of project scheduling and costing techniques and tools are used to measure the accuracy. The new systematic techniques increase project outcomes and also reduce the uncertainty from the projects.  This study will leads to examine thoroughly project scheduling and project costing. Then this study will guide project managers how to develop a project schedule and what factors are effecting on the project scheduling and a sample project schedule will also provide for project managers and students of project management. After that the major sources of project costing and the method to calculate the project cost will also provide. And the sample project costing sheet is also develop in this study. Both project scheduling and project costing will develop the professionalism among project managers and students of project managers which they can never think before this study and also enhance project outcomes. Keywords: Project Scheduling, Project Costing, Uncertainty Handling and Project Succes

    A hybrid egalitarian bargaining game-DEA and sustainable network design approach for evaluating, selecting and scheduling urban road construction projects

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    Selecting and scheduling urban road construction projects (URCPs) is inherently an Urban Network Design Problem (UNDP) with a complex decision making process. Recently some studies have focused on sustainable UNDP, using different mathematical methods. In this paper, first a new network data envelopment analysis (NDEA) model has been developed. Then, considering sustainability dimensions, by integrating data envelopment analysis (DEA), game theory and sustainable UNDP, a bi-level model has been proposed for selecting and scheduling URCPs. A meta-heuristic algorithm is proposed to solve the presented bi-level model. Different test instances are solved to show the acceptable performance of proposed algorithm in both solution quality and execution time. Afterwards, the proposed model is applied to study the problem of urban road construction projects selection in a real-world case study of urban transportation network of Isfahan city in Iran. The results show that by applying obtained solution the environmental and social performance of the network has been improved and the performance of the network is almost efficient in all evaluation periods

    Time-Dependent Transportation Network Design considering Construction Impact

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    Network Maintenance and Capacity Management with Applications in Transportation

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    abstract: This research develops heuristics to manage both mandatory and optional network capacity reductions to better serve the network flows. The main application discussed relates to transportation networks, and flow cost relates to travel cost of users of the network. Temporary mandatory capacity reductions are required by maintenance activities. The objective of managing maintenance activities and the attendant temporary network capacity reductions is to schedule the required segment closures so that all maintenance work can be completed on time, and the total flow cost over the maintenance period is minimized for different types of flows. The goal of optional network capacity reduction is to selectively reduce the capacity of some links to improve the overall efficiency of user-optimized flows, where each traveler takes the route that minimizes the traveler’s trip cost. In this dissertation, both managing mandatory and optional network capacity reductions are addressed with the consideration of network-wide flow diversions due to changed link capacities. This research first investigates the maintenance scheduling in transportation networks with service vehicles (e.g., truck fleets and passenger transport fleets), where these vehicles are assumed to take the system-optimized routes that minimize the total travel cost of the fleet. This problem is solved with the randomized fixed-and-optimize heuristic developed. This research also investigates the maintenance scheduling in networks with multi-modal traffic that consists of (1) regular human-driven cars with user-optimized routing and (2) self-driving vehicles with system-optimized routing. An iterative mixed flow assignment algorithm is developed to obtain the multi-modal traffic assignment resulting from a maintenance schedule. The genetic algorithm with multi-point crossover is applied to obtain a good schedule. Based on the Braess’ paradox that removing some links may alleviate the congestion of user-optimized flows, this research generalizes the Braess’ paradox to reduce the capacity of selected links to improve the efficiency of the resultant user-optimized flows. A heuristic is developed to identify links to reduce capacity, and the corresponding capacity reduction amounts, to get more efficient total flows. Experiments on real networks demonstrate the generalized Braess’ paradox exists in reality, and the heuristic developed solves real-world test cases even when commercial solvers fail.Dissertation/ThesisDoctoral Dissertation Industrial Engineering 201

    Modelos de optimización para el diseño estratégico-táctico de una red de transporte intermodal

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    [ES] En esta tesis doctoral se desarrollan modelos de programación matemática para el diseño estratégico-táctico de una red de transporte intermodal que combina dos tipos de problemas de decisiones: la localización de instalaciones y el diseño de la red de transporte. Esta combinación se reconoce en la literatura como problemas combinados LI-DR. El problema combinado se estudia para una situación real y se analizan el comportamiento de la solución óptima, a partir de distintos aspectos como: la disponibilidad del presupuesto de inversión, capacidad de las instalaciones intermodales, múltiples periodos de decisiones, interdependencia en la priorización de las decisiones, múltiples fuentes de financiación y criterios de optimización para las tres dimensiones de sostenibilidad. Para la situación real se referencian las condiciones de acceso y conectividad de la Zona de Desarrollo Económico y Social (ZODES) Magdalena Medio del departamento de Bolívar en Colombia, y el potencial de la industria agroalimentaria para esta subregión. Con el propósito de identificar factores clave que perfilen la formulación respecto a la composición y funcionamiento de los sistemas intermodales y en los problemas combinados LI-DR se analiza la literatura desde estas dos perspectivas. El análisis de la literatura ha permitido aportar dos clasificaciones novedosas e identificar retos para la investigación futura. Para la formulación de los modelos se lleva a cabo la sistemática de pasos definidos para la aplicación de las técnicas de programación matemática. Con estos pasos se logra transformar el problema del mundo real a un problema manejable con estas técnicas. La transformación favorece la interpretación matemática del problema combinado LI-DR intermodal, la modelación de los datos y la definición de una estructura de red de entrada para indexar las decisiones estratégicas y tácticas. Los modelos de programación matemática se construyen de manera gradual. En concreto, se proponen 2 versiones que se representan en 5 variantes. Se comienza formulando un modelo de programación lineal entero-mixto (MPLEM) mono-periodo para analizar, desde un enfoque económico, la sensibilidad de las capacidades del sistema intermodal, la capacidad financiera de los tomadores de decisiones y la variación de la demanda. A continuación, sobre la base de este modelo se propone un MPLEM multi-periodo y dos variantes para validar las condiciones de interdependencia en la toma de decisiones estratégica y la participación de múltiples actores en la financiación de los proyectos de inversión. Finalmente, se formula un MPLEM multi-objetivo para optimizar simultáneamente las tres dimensiones de sostenibilidad. Para resolver y validar los modelos se implementaron dos esquemas de resolución. En los esquemas se utilizan los lenguajes de programación R y Python con el software de optimización matemática Gurobi Optimizer. Se realizan experimentos numéricos para distintos escenarios y se analiza el comportamiento de las soluciones considerando distintos valores a los parámetros. Los resultados obtenidos permiten comprobar la utilidad de los modelos matemáticos e identificar las principales limitaciones y futuras líneas de trabajo.[CA] En aquesta tesi doctoral es desenvolupen models de programació matemàtica per al disseny estratègic-tàctic d'una xarxa de transport intermodal que combina dos tipus de problemes de decisions: la localització d'instal·lacions i el disseny de la xarxa de transport. Aquesta combinació es reconeix en la literatura com problemes combinats LI-DR. El problema combinat s'estudia per a una situació real i s'analitzen el comportament de la solució òptima, a partir de diferents aspectes com: la disponibilitat de l'pressupost d'inversió, capacitat de les instal·lacions intermodals, múltiples períodes de decisions, interdependència en la priorització de les decisions, múltiples fonts de finançament i criteris d'optimització per a les tres dimensions de sostenibilitat. Per a la situació real es referencien les condicions d'accés i connectivitat de la Zona de Desenvolupament Econòmic i Social (ZODES) Magdalena Medio de el departament de Bolívar a Colòmbia, i el potencial de la indústria agroalimentària per a aquesta subregió. Amb el propòsit d'identificar factors clau que perfilin la formulació respecte a la composició i funcionament dels sistemes intermodals i en els problemes combinats LI-DR s'analitza la literatura des d'aquestes dues perspectives. L'anàlisi de la literatura ha permès aportar dues classificacions noves i identificar reptes per a la investigació futura. Per a la formulació dels models es porta a terme la sistemàtica de passos definits per l'aplicació de les tècniques de programació matemàtica. Amb aquests passos s'aconsegueix transformar el problema de l'món real a un problema manejable amb aquestes tècniques. La transformació afavoreix la interpretació matemàtica de el problema combinat LI-DR intermodal, la modelació de les dades i la definició d'una estructura de xarxa d'entrada per indexar les decisions estratègiques i tàctiques. Els models de programació matemàtica es construeixen de manera gradual. En concret, es proposen 2 versions que es representen en 5 variants. Es comença formulant un model de programació lineal sencer-mixt (MPLEM) mono-període per analitzar, des d'un enfocament econòmic, la sensibilitat de les capacitats de sistema intermodal, la capacitat financera dels prenedors de decisions i la variació de la demanda. A continuació, sobre la base d'aquest model es proposa un MPLEM multi-període i dues variants per validar les condicions d'interdependència en la presa de decisions estratègica i la participació de múltiples actors en el finançament dels projectes d'inversió. Finalment, es formula un MPLEM multi-objectiu per optimitzar simultàniament les tres dimensions de sostenibilitat. Per resoldre i validar els models es van implementar dos esquemes de resolució. En els esquemes s'utilitzen els llenguatges de programació R i Python amb el programari d'optimització matemàtica Gurobi Optimizer. Es realitzen experiments numèrics per a diferents escenaris i s'analitza el comportament de les solucions considerant diferents valors als paràmetres. Els resultats obtinguts permeten comprovar la utilitat dels models matemàtics i identificar les principals limitacions i futures línies de treball.[EN] In this doctoral thesis, mathematical programming models are developed aiming at the strategic-tactical design of an intermodal transport network that combines two types of decision problems: the location of facilities and the transport network design. In the literature, this combination is recognized as combined LI-DR problems. The combined problem is studied for a real situation and the performance of the optimal solution is analyzed in relation to different aspects such as the investment budget availability, the intermodal facilities capacity, multiple decision periods, interdependence in the prioritization of the decisions, multiple sources of funding and optimization criteria for the three dimensions of sustainability. In what concern to the real situation, the access and connectivity conditions of the Magdalena Medio Economic and Social Development Zone (ZODES, for its acronym in Spanish) of the Bolívar department in Colombia, and the potential of the agri-food industry for this subregion, are considered. Aiming the identification of key factors that outlines the formulation regarding the composition and operation of intermodal systems and, in combined LI-DR problems, the literature is reviewed from these two perspectives. The literature analysis has made it possible to provide two novel classifications and to identify challenges for future research. The formulation of models follows the systematic steps already defined for the application of mathematical programming techniques. Following these steps, it is possible to transform the problem from a real-world problem to a manageable one. The transformation promotes the mathematical interpretation of the intermodal LI-DR combined problem, the data modeling, and the definition of an input network structure to index strategic and tactical decisions. Mathematical programming models are built gradually. Specifically, 2 versions are proposed, which are represented by 5 variants. Firstly, it is formulated a single-period mixed-integer linear programming model (MILPM) in order to analyze, from an economic perspective, the sensitivity of the intermodal system capacities, the financial capacity of the decision-makers, and the demand changes. Based on the aforementioned model, a multi-period MILPM and two variants are proposed aiming to validate the conditions of interdependence in strategic decision-making and the participation of multiple actors in the investment projects financing. Finally, a multi-objective MILPM is formulated to simultaneously optimize all three dimensions of sustainability. To solve and validate the models, two resolution schemes were implemented. The schematics use the R and Python programming languages with the mathematical optimization software Gurobi Optimizer. Numerical tests are carried out for different scenarios and the performance of the solutions is analyzed considering different values for the parameters. The results obtained allow us to verify the usefulness of the models proposed and identify the main limitations and future lines of work.Agamez Arias, ADM. (2021). Modelos de optimización para el diseño estratégico-táctico de una red de transporte intermodal [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/177015TESI
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