Schedule Risk Research Articles

A risk management-based evaluation of inventory allocations for make-to-order production

Today's manufacturing companies offer products catered to customers’ needs within tight schedules and stringent cost control. Commonly make-to-order strategies are employed for which production is frequently scheduled ahead of order commitment while considering the stochastic nature of modern manufacturing systems. Inventory at the right stage may reduce the entailed risk of tardiness. But today's inventory planning approaches don’t fully consider scheduling risk. This paper addresses this shortcoming, presenting an evaluation of inventory allocations along the risks of production schedule and stock out allowing identification of critical items to mitigate delays. A case study in the machine tools industry verifies applicability.

Empirical Findings about Risk and Risk Mitigating Actions from a Legacy Archive of a Large Design Organization

Understanding how to mitigate project risk is an important aspect of project management. Risks that are not properly managed can lead to cost overruns, schedule delays, wasted manpower and effort, and failure of the project artifact. Deciding which risk mitigating actions to pursue has largely been an intuitive endeavor, relying on expert opinions which are typically opaque. A more quantitative approach, based on results from actual past projects, is needed. This paper presents empirical findings relating past risk mitigating actions and project outcomes such as project cost, project schedule, and project risk. The findings are based on analysis of a legacy archive of project risk and risk mitigating actions from a large design organization, as well as from categorizing the different types of actions found in the archive based on a taxonomy developed using the archive itself, and analyzing the outcomes of those different types of actions. This study presents a more quantitative understanding of the relationship between a project state, the risks involved, and risk-mitigating actions taken during the project. This will enable improved decision making with better knowledge of the possible consequences of different types of risk mitigating actions and their effects in decreasing project risk.

Scheduling Critical Activities of Stochastic Projects Management

In this paper, we consider the problem of stochastic project network when some or all activities are interrupted. An approach has been built to schedule the critical activities, by constructing some expressions based on the project lateness costs due to the interruption activities. Two simple example are presented to validate our approach.
 Key words: Project Management, Project scheduling, Stochastic activity duration, Stochastic PERT. 
 Introduction
 Recently, Projects planning and optimal timing, under uncertainty are extremely critical for many organizations, see [19]. Having an effective mathematical model will give project managers a significant tool for replanning projects allocation decisions in response events and outcomes. As a result, the uncertainty associated with such risky projects should be reduced. 
 No one factor can account for, or prevent, failure in a project. It is common practice for a project team to develop a comprehensive risk assessment and risk management plan. Identifying the most critical activities with regard to schedule risk is a problem faced by all project managers.
 The problem of identifying critical activities (CA) in a deterministic network is well understood, by standard Critical Path Method (CPM) known as Program Evaluation and Review Technique (PERT). Since a project could be delayed if these activities were not completed in the scheduled time. The classical PERT method is the probably is the best-known mechanism for considering the stochastic nature of activity durations, in which it is possible to develop estimates of the uncertainty of the project make span. For more details see [8] & [10 ].

Requirements-based execution time prediction of a partitioned real-time system using I/O and SLOC estimates

Predicting computer processing requirements of a completed system early in the design and development lifecycle of that system is challenging. Software requirements and avionic or hardware systems often mature in parallel, and, in early stages of design, uncertainty over processing requirements makes determination of processing architecture difficult. Later in the design process, as details become finalized and prototypes are developed, estimations become increasingly more accurate. However, waiting until later in the lifecycle to make architectural changes causes those changes to be more costly and introduces schedule and technical risks. The sooner processing needs are determined and the corresponding system architecture is established, the more easily an appropriate processing platform can be incorporated into the design. This paper describes a novel approach for estimating processor utilization early in the lifecycle of a large, real-time software development project: NASA's Orion Crew Exploration Vehicle flight software. The approach uses available requirements documentation as a basis of the estimate and decouples input/output (I/O)- and computation-based processing by estimating each separately then combining the results. This approach is unique because it can be used to estimate the execution time for unwritten or partially specified software, in addition to giving a specific contribution for I/O. The methodology for estimating I/O processing is based on quantifying data, while the methodology for estimating algorithmic processing is based on approximated code size. Results can be used as an aid to predict target processor types and quantities, allocate software to processors, predict communication bandwidth utilization, and manage processor margins.

Construction Project Scheduling Risk Analysis Using Event Chain Methodology: An Example of Airport Terminal Project

This paper describes a new perspective to consider and quantify uncertainty in construction schedules. In the study, a methodology was presented by modeling construction project scheduling using event chains, classification of the events and event chains, identification of critical events, analysis of effect of the events on project duration, and chance of project completion. To demonstrate the applicability and effectiveness of the proposed methodology, a real airport terminal example is provided. Moreover, schedule risk analysis system and risk break down structure are also developed as an essential part.

An Information-Theoretic Metric of System Complexity With Application to Engineering System Design

System complexity is considered a key driver of the inability of current system design practices to at times not recognize performance, cost, and schedule risks as they emerge. We present here a definition of system complexity and a quantitative metric for measuring that complexity based on information theory. We also derive sensitivity indices that indicate the fraction of complexity that can be reduced if more about certain factors of a system can become known. This information can be used as part of a resource allocation procedure aimed at reducing system complexity. Our methods incorporate Gaussian process emulators of expensive computer simulation models and account for both model inadequacy and code uncertainty. We demonstrate our methodology on a candidate design of an infantry fighting vehicle.

Challenges of Loss to Follow-up in Tuberculosis Research

BackgroundIn studies evaluating methods for diagnosing tuberculosis (TB), follow-up to verify the presence or absence of active TB is crucial and high dropout rates may significantly affect the validity of the results. In a study assessing the diagnostic performance of the QuantiFERON®-TB Gold In-Tube test in TB suspect children in Tanzania, factors influencing patient adherence to attend follow-up examinations and reasons for not attending were examined.MethodsIn 160 children who attended and 102 children who did not attend scheduled 2-month follow-up baseline health characteristics, demographic data and risk factors for not attending follow-up were determined. Qualitative interviews were used to understand patient and caretakers reasons for not returning for scheduled follow-up.ResultsBeing treated for active TB in the DOTS program (OR: 4.14; 95% CI:1.99–8.62;p-value<0.001) and receiving money for the bus fare (OR:129; 95% CI 16->100;P-value<0.001) were positive predictors for attending follow-up at 2 months, and 21/85(25%) of children not attending scheduled follow-up had died. Interviews revealed that limited financial resources, i.e. lack of money for transportation and poor communication, were related to non-adherence.ConclusionPatients lost to follow-up is a potential problem for TB research. Receiving money for transportation to the hospital and communication is crucial for adherence to follow-up conducted at a study facility. Strategies to ensure follow-up should be part of any study protocol.

My COCOMO: Building Your Own Incremental Software Build Estimation Tools

AbstractThis paper describes work performed in Rolls‐Royce to develop an Incremental Software Build Cost and Schedule estimation tool. The software builds incorporated in the analysis were performed over a period of 10 years with a reasonably consistent team of engineers and software development environment ‐ hence many of the environmental factors developed in software estimation tools like COCOMO (1) were effectively held constant in this study. This allowed the correlation to concentrate on measuring the effects of team size and process change on cost and schedule estimates. These correlations have been integrated with the COCOMO model to create a system that can account for team size for both cost and schedule estimation – “My COCOMO”.The first part of the paper describes factors that can influence the measurement of “effort” and how these may add noise to correlations.The second part of the paper describes how team size can be incorporated into the estimation model to reduce scatter in predictions, and concludes by showing how the resulting correlations can be incorporated into an incremental software build estimation tool which accounts for the level of cost and schedule risk the project is prepared to take when developing a software build.The third part describes the effect of a process change that was introduced and the statistical verification of the significance of the process change on the effort required for software builds.

Can carbon dioxide storage site qualification help meet a 2015 deadline?

Carbon dioxide capture and geological storage demonstration projects are exposed to a unique and complex set of risks due to high capital investment costs, unpredictable political incentives and novel technology. Deadlines for start-up may be attached to public funding and can create incentives for projects to deviate away from a commercial investment model and accept higher risks early in the project. A project schedule risk analysis is performed for an example carbon dioxide capture and geological storage demonstration project that is designed to represent a real-world project. Front-loading of project costs is examined as a mechanism for increasing the probability of meeting an imposed 2015 deadline for the start of operations. The increased exposure this approach may create to not finding adequate carbon dioxide storage reserves is studied in the context of the storage site qualification process described in the CO2qualstore joint industry guideline.

Modification of Advanced Programmatic Risk Analysis and Management Model for the Whole Project Life Cycle’s Risks

The advanced programmatic risk analysis and management model (APRAM) is one of the recently developed methods that can be used for risk analysis and management purposes considering schedule, cost, and quality risks simultaneously. However, this model considers those failure risks that occur only over the design and construction phases of a project's life cycle. While it can be sufficient for some projects for which the required cost during the operating life is much less than the budget required over the construction period, it should be modified in relation to infrastructure projects because the associated costs during the operating life cycle are significant. In this paper, a modified APRAM is proposed, which can consider potential risks that might occur over the entire life cycle of the project, including technical and managerial failure risks. Therefore, the modified model can be used as an efficient decision-support tool for construction managers in the housing industry in which various alternatives might be technically available. The modified method is demonstrated by using a real building project, and this demonstration shows that it can be employed efficiently by construction managers. The Delphi method was applied in order to figure out the failure events and their associated probabilities. The results show that although the initial cost of a cold-formed steel structural system is higher than a conventional construction system, the former's failure cost is much lower than the latter's.

An overlapping-based process model for managing schedule and cost risk in product development

Overlapping between development activities stemming from concurrent engineering may not only reduce duration of a project but also create rework risk. This article presents a process modeling and analysis technique for managing complex product development projects using optimization and simulation techniques. In order to analyze the forced overlapped process with lead–risk, we propose evolution and sensitivity design structure matrix for reflecting overlapping and their impact on the degree of activity sensitivity and evolution in the process model. Using the design structure matrix, we present the schedule and cost model associated with iteration, overlapping, and rework by incorporating many more general characteristics of complex design processes. The model can be used for better project planning and control by identifying overlapping and risk for process improvements, and for evaluating alternative planning and execution strategies. An industrial example, a tactics aerocraft preliminary development design process at a company, is provided to illustrate the utility of the model using optimization and discrete-event simulation. The optimization model maximizes the compressed time associated with overlapping and yields several managerial insights, including optimization analysis of project activity sequence, how overlapping and rework risk impact on project schedule and cost, trading off schedule and cost risk.

Schedule Risk Analysis of ICT Infrastructure Projects

Scheduling a project is an inexact process in that it tries to predict the future. An ICT infrastructure project is a combination of interrelated activities that must be performed in a certain order of completion. To cut development costs and meet tight deadlines in ICT software Infrastructure Projects, managers need to understand some key doubts about the standard scheduling methods and how to use a schedule risk analysis to provide information crucial to an ICT Infrastructure Project's success before they embark on their ICT Infrastructure Project. This study deals with the benefit of conducting schedule risk analysis on an ICT Infrastructure Project. It is shown that such risk analysis has the potential to provide key information for ICT Infrastructure project managers in advance so that risk mitigation plans can be developed and implemented in time.

Integrating Systems Engineering Into the USAF Academy Capstone Gas Turbine Engine Course

This paper is intended to serve as a template for incorporating technical management majors into a traditional engineering design course. In 2002, the Secretary of the Air Force encouraged the United States Air Force (USAF) Academy to initiate a new interdisciplinary academic major related to systems engineering. This direction was given in an effort to help meet the Air Force’s growing need for “systems” minded officers to manage the development and acquisition of its ever more complex weapons systems. The curriculum for the new systems engineering management (SEM) major is related to the “engineering of large, complex systems and the integration of the many subsystems that comprise the larger system” and differs in the level of technical content from the traditional engineering major. The program allows emphasis in specific cadet—selected engineering tracks with additional course work in human systems, operations research, and program management. Specifically, this paper documents how individual SEM majors have been integrated into aeronautical engineering design teams within a senior level capstone course to complete the preliminary design of a gas turbine engine. As the Aeronautical Engineering (AE) cadets performed the detailed engine design, the SEM cadets were responsible for tracking performance, cost, schedule, and technical risk. Internal and external student assessments indicate that this integration has been successful at exposing both the AE majors and the SEM majors to the benefits of “systems thinking” by giving all the opportunity to employ SE tools in the context of a realistic aircraft engine design project.

Reliability as an Independent Variable Applied to Liquid Rocket Engine Hot Fire Test Plans

Manufacturers lack an adequatemethod to balance performance, reliability, and affordability. The reliability-asan-independent-variable methodology is the solution proposed by expressing quantitatively the reliability trade space as ranges of a number of hardware sets and a number of hot-fire tests necessary to develop and qualify/certify a liquid rocket engine against a stated reliability requirement. Therefore, reliability-as-an-independent-variable becomes one of the key decision parameters in early tradeoff studies for liquid rocket engines because the reliability trade space directly influences the performance requirements and, as a result, the affordability. The overall solution strategy of reliability-as-an-independent-variable is based on the Bayesian statistical framework using either the planned or actual number of hot-fire tests. The planned hot-fire test results may include test failures to simulate the typical design-fail-fix-test cycles present in liquid rocket engine development programs in order to provide the schedule and cost risk impacts for early tradeoff studies. The reliability-as-an-independent-variable methodology is exemplarily applied to the actual hot-fire test history of the F-1, the space shuttle main engine, and the RS-68 liquid rocket engine, showing adequate agreement between computed results and actual flight engine reliability.

Measuring the efficiency of project control using fictitious and empirical project data

Dynamic scheduling refers to the integration of three important phases in the life cycle of a project: baseline scheduling, schedule risk analysis and project control. In this paper, the efficiency of controlling a project is measured and evaluated using a Monte-Carlo simulation study on fictitious and empirical project data. In the study, the construction of a project baseline schedule acts as a point-of-reference for the schedule risk analysis and project control phases. The sensitivity information obtained by the schedule risk analyses (SRA) and the earned value management (EVM) information obtained during project control serve as early warning control parameters that trigger corrective actions to bring projects back on track in case of problems. The focus in this paper lies on the time performance of a project, and not on the prediction and controlling of the project costs. The contribution of this paper is twofold. First, this paper summarizes the main conclusions of various experiments performed in a large simulation study on the efficiency of project control techniques and the ability to trigger corrective actions in case of project problems. The main purpose of these simulation experiments is to understand why EVM and/or SRA work so well in some projects and fail so miserably in others. This study has been awarded by the International Project Management Association in 2008 on the IPMA world congress in Rome (Italy). Secondly, the paper compares the results obtained on fictitious project data with additional tests performed on a set of real-life data from 8 Belgian companies from various sectors.

Simulação aplicada ao gerenciamento de projetos: uma revisão

O objetivo deste artigo é mostrar uma revisão da literatura sobre o tema Simulação Aplicada ao Gerenciamento de Projetos no contexto dos últimos 20 anos. O mesmo revê as principais metodologias de Simulação, bem como algumas de suas propriedades, que motivaram a aplicação da Simulação em gerenciamento de projetos. Além disso, são revistos marcos históricos sobre o tema, desde a proposição da Simulação de Monte Carlo como solução para as limitações da metodologia PERT/CPM. Em acréscimo, a pesquisa procura mapear o tema, por meio de estratificações, de maneira a proporcionar uma visão holística sobre o assunto. Como resultado final, será possível observar algumas importantes relações e tendências entre as estratificações, como a elevada utilização da Simulação de Eventos Discretos e da Simulação de Monte Carlo para a gestão de riscos de prazo e de custo. Tais aplicações estão normalmente associadas a projetos de elevados riscos, como empreendimentos civis, projetos de desenvolvimento de softwares, de Engenharia de design e projetos da indústria de óleo &amp; gás.

Analysis on the Transmission Type of Programe Schedule Risk

Based on the program characteristics, putting the program schedule management as the starting point , this paper analyzes the characteristics and transmission type of the program schedule risk. Combined with the practice of the program schedule management, it provides the risk-control method to avoid the program schedule risk.

A statistical model for estimating combined schedule and cost risks

In this integrated approach to project risk management, schedule risk is represented by the distribution of delay in project completion and budget risk is represented by the distribution of total project cost, which is conditional on the schedule risk. The derived expression for budget risk takes into account the dependence on schedule risk and is used to determine the budget reserve required to achieve a specific level of protection against schedule risk. The result extends previous research on delay-related cost contingency analysis.

RISK ASSESSMENT AND ACTION SELECTION IN PRELIMINARY DESIGN

New product development (NPD) has typically had strategic implications for the success and prosperity of an organization. This paper applied refined failure mode and effect analysis and genetic algorithm techniques to develop and establish an integrated risk analysis model for improving preliminary design of NPD. Three core items, technological performance, cost, and schedule risk, were used to improve the process of preliminary design and resource allocation in NPD projects. Risk severity, occurrence, and correlation characteristics are collected for each core item. A real study case was implemented to conclude an improving design decision and process change for NPD project.

Analysis and Evaluation of Project Cost Risk Based on BP Algorithm

Standing at the perspective of the project management, this thesis, from the relation between schedule, quality and cost, analyzes how the project cost was influenced by the schedule risk and quality risk, assesses the total cost risk of the project with artificial neural network BP algorithm, and determines the most sensitive factors of the project cost risk, which could provide reference for the project managers to control the project cost risk.