Activity nets: A guided tour through some recent developments

Elmaghraby, Salah E.

doi:10.1016/0377-2217(94)00184-e

Cited by 118 publications

(61 citation statements)

References 33 publications

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“…Esto quiere decir que, si por ejemplo, el problema de limitación de recursos se trata desde un principio, tomando todas aquellas decisiones que sean necesarias para resolver aquellos conflictos de carga/capacidad que se vayan detectando en los diferentes niveles de descomposición-agregación de los proyectos y sus recursos, en los también diferentes horizontes de tiempo, entonces al final se tendrán problemas de programación al nivel operativo (el mayor nivel de detalle), factibles de ser resueltos con decisiones operativas (utilización de equipos o máquinas alternativas, horas extras, etc.). Lo contrario significa que al final en lo operativo, se tienen tal cantidad de conflictos entre la demanda de recursos y la oferta de los mismos en un período específico, que las armas operativas disponibles en ese nivel no serán útiles para resolverlos y por lo tanto la consecuencia lógica es un mayor retraso en los proyectos con relación a la fecha de finalización originalmente propuesta ( [Elmaghraby, 1977], [Elmaghraby, 1995]). …”

Section: Descomposición -Agregación Por Nivelesunclassified

Planificación Jerárquica con Análisis de Carga /Capacidad

Motoa¹,

Sastrón²

2011

IyC

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La planificación jerárquica de múltiples proyectos, surge como una opción robusta y potente, para resolver el problema de gestión del sistema global. La propuesta se basa en la construcción de una estructura de descomposición-agregación de los proyectos y los recursos, con múltiples niveles, en la cual , los niveles más altos presentan los datos más agregados, con horizontes de tiempo más largos y los niveles inferiores son más detallados y con horizontes más cortos. Cada nivel tiene asociado un modelo conformado por

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Section: Descomposición -Agregación Por Nivelesunclassified

Planificación Jerárquica con Análisis de Carga /Capacidad

Motoa¹,

Sastrón²

2011

IyC

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“…Activity-on-arc [project evaluation and review technique (PERT)], activity-on-node, and other flowchart-type representations are widely used to represent activities and their precedence relationships. Despite the enormous amount of research on activity networks (see [32] for an excellent review) using these formats, they are not convenient for representing a large number of interfaces or for comparing alternative process architectures. The visual representation is too busy, making it difficult to discern architectural differences.…”

Section: A Pd As a Complex Web Of Interactionsmentioning

confidence: 99%

“…The model can also be extended to account for resource constraints in the determination of active activities [85], using available algorithms (e.g., [8], [18], and [32]). This extension would further emphasize the advantages of iterative overlapping.…”

Section: Next Steps and Possible Extensionsmentioning

confidence: 99%

Modeling impacts of process architecture on cost and schedule risk in product development

Browning

Eppinger

2002

IEEE Trans. Eng. Manage.

385

293

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Abstract-To gain competitive leverage, firms that design and develop complex products seek to increase the efficiency and predictability of their development processes. Process improvement is facilitated by the development and use of models that account for and illuminate important characteristics of the process. Iteration is a fundamental but often unaddressed feature of product development (PD) processes. Its impact is mediated by the architecture of a process, i.e., its constituent activities and their interactions. This paper integrates several important characteristics of PD processes into a single model, highlighting the effects of varying process architecture. The PD process is modeled as a network of activities that exchange deliverables. Each activity has an uncertain duration and cost, an improvement curve, and risks of rework based on changes in its inputs. A work policy governs the timing of activity execution and deliverable exchange (and thus the amount of activity concurrency). The model is analyzed via simulation, which outputs sample cost and schedule outcome distributions. Varying the process architecture input varies the output distributions. Each distribution is used with a target and an impact function to determine a risk factor. Alternative process architectures are compared, revealing opportunities to trade cost and schedule risk. Example results and applications are shown for an industrial process, the preliminary design of an uninhabited combat aerial vehicle. The model yields and reinforces several managerial insights, including: how rework cascades through a PD process, trading off cost and schedule risk, interface criticality, and occasions for iterative overlapping.Index Terms-Activity network, budgeting, cycle time, design iteration, design structure matrix, engineering design management, process architecture, process modeling, process structure, product development, rework, risk management.

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“…The early activity net-based techniques for project planning, task scheduling and control, including the Critical Path Method (CPM) [8] and the Project Evaluation and Review Technique (PERT) [9], form the foundation for many project management models. Generalized precedence relations (GPRs) [8] were then proposed to extend CPM from "strict precedence" (i.e. activity finish-to-start relationship) to four possible relationships (i.e., start-to start, finish-to-finish, start-to-finish, and finish-to-start).…”

Section: An Overview Of Approaches To Process Modelmentioning

confidence: 99%