Rework Cycle Research Articles

Critical Thinking Skills Enhancement through System Dynamics-Based Games: Insights from the Project Management Board Game Project

This study aims to explore and discuss the role of systems thinking and system dynamics-assisted games in enhancing critical thinking skills in learners. In more detail, the study relies on the use of a system dynamics-based interactive learning environment related to project management issues, followed by systems thinking-supported debriefing sessions. The interactive learning environment was developed and used in the form of a single-player, online, computer-based game. The game was designed to mimic all the necessary planning and operational activities needed to organize a wedding ceremony. The acquisition of critical thinking skills in learners was evaluated in three main ways: (1) players’ performances were analyzed through a scoring system embedded in the game that considers several performance dimensions; (2) feedback from the players was collected and analyzed by using basic content analysis; (3) players’ performances were analyzed using five main categories of structures that are typical of project management domains, i.e., project features, the rework cycle, project control, ripple effects, and knock-on effects. The findings show that the joint use of system dynamics and systems thinking tools and principles within a gaming environment has the potential to facilitate and enhance the acquisition of critical thinking skills in learners and may also provide valid support for educators and practitioners interested in the enhancement of project management skills.

DESIGN PROCESS MODELLING TO MEASURE ENGINEERING PRODUCTIVITY IN BUILDING DESIGN

AbstractA multi-domain Matrix (MDM) is used to identify and analyse rework loops within the Building Design (BD) process caused by building regulations. To model this process, we used information from official documents, plans of work, email archives, and anecdotal evidence as a case study. Findings reveal that MDM can identify the rework loops caused by building regulations, this information forms the basis to improve current BD processes. The complexity of the rework loop including the processes, people and, deliverables involved in the rework loop is also identified. Further analysis can also use the MDM to estimate the costs incurred with each rework cycle. This MDM can also identify rework loops in other engineering design processes due to design changes.This study is part of a PhD project exploring engineering productivity in the construction industry using DRM. The results present an MDM that provides situation-specific insight, offering areas of process improvement, and support through engineering productivity measurement. This is one of the few studies that models rework loops in the BD process caused by regulations.

Design and management of software development projects under rework uncertainty: a study using system dynamics

ABSTRACT Despite proper planning and scheduling, project execution is challenging, and one critical factor is uncertainty duringthe project implementation process. This study presents a system dynamics (SD) model as a decision-support system for model-based decision-making that considers the uncertainty of rework generation by predicting dynamic and complex project behaviour. The SD model was developedalong with a rework cycle that principally contributes to rework generation. The uncertainty ofrework generation and project performance werevisualized and integrated into decision-making components.Six different scenarios involving hiring and overtime usage were explored to ensure project performance whendesigning a feasible project plan.The novelty of this study lies inthe decision-making process for obtaining the best planning alternatives under uncertainty and project conditions. Actions should be implemented thatpredict and analyse improvised project planningprocesses and control model-based decision-making under uncertainty.

Reduced Rework Through Data Analytics and Machine Learning – A Three Level Development Approach

In many production companies, rework of products that do not meet the defined quality level is a common practice. Usually organized at the end-of-line in form of test and rework cycles the goal is that no defect \textquotedblescapes\textquotedbl to the customer. Only in rare cases, a systematic problem solving is triggered through a rework process to identify and remove the root cause. In the EIT Manufacturing project IVE a data-driven problem-solving tool is being developed with the focus on rework. Through a three-level development approach, the goal is to significantly reduce rework effort as well as the time to detect and analyze a problem. In the first level, an error score is being developed to give the shop floor team an overview about error clusters and to help them decide which errors to focus on. In the second level, machine learning is used to give action recommendations to the rework teams and to predict the needed work force depending on the production program. In contrast to the first two levels, which aim to reduce the amount of rework, the third level aims to completely avoid rework through in-line action recommendations based on data from preceding processes. To validate and demonstrate the usefulness of a data-driven approach as well as the implementation of machine learning algorithms to companies, the developed tool will be implemented in the ``process learning factory CiP''. For this purpose, a rework station will be created and designed to meet the specific needs. If the implementation is successful, the concept can also be transferred to other learning factories.

A framework for achieving sustainability by overcoming the challenges of the construction supply chain during the design process

Abstract This paper aims to develop a framework to achieve sustainability by overcoming the challenges of the construction supply chain (CCSC) during the design process. To achieve this, two approaches, namely theoretical and practical, were used to accomplish four objectives. For the theoretical approach, based on literature review and case studies, the objective used was to identify, classify and validate the challenges that the construction supply chain (CSC) encounter. For the practical approach, a survey questionnaire was employed to quantify the CCSC and investigate the perception of architectural design firms (ADFs) in Egypt towards achieving sustainability by overcoming the CCSC during the design process. Based on the results, the research developed a framework to overcome the CCSC as an approach towards achieving sustainability in construction projects during the design process. The research identified and validated 20 challenges that the CSC encounter towards achieving sustainability during the design process. These challenges were classified under four categories, namely (1) design and technical process; (2) coordination, information flow and accuracy; (3) material specification, technology, supplier rework and whole life cycle cost; and (4) skills gap of the qualified architects and design managers and non-compliance to building codes, regulations, laws and standards. In addition, a survey questionnaire was employed to rank these challenges according to their importance on 1–5 Likert scale using the measure of central tendency and dispersion and relative importance index (RII).

Distinct petrographic responses to basin reorganization across the Triassic–Jurassic boundary in the southwestern Barents Sea

AbstractA general shift towards higher mineralogical and textural maturity changes the reservoir character across the Triassic–Jurassic transition in the southwestern Barents Sea basin (SWBSB), largely affecting the hydrocarbon prospectivity in the region. Petrographic and geochronological provenance data presented in this paper suggest that the shift from mineralogically immature to mature sandstones initiated during the deposition of the Norian–Rhaetian Fruholmen Formation, and varies with basin location. Strong contrasts between the Fruholmen Formation and underlying formations are associated with proximity to the rejuvenated Caledonian and Fennoscandian hinterlands and are mainly restricted to the southern basin margins. In the basin interior, subtle petrographic variations between the Fruholmen Formation and older Triassic sandstones reflect a distal position relative to the southern hinterland. The long‐lived misconception of a regional compositional contrast in the Arctic at the turn of the Norian can be attributed to higher sampling frequency associated with hydrocarbon exploration activity along the southern basin margins, and masking by increased annual precipitation and subsequent reworking during the Jurassic. Geothermal signatures and rearrangement of ferric clay material across the Carnian–Norian transition support a recycled origin for the Fruholmen Formation in the basin interior. As the closest tectonically active region at the time, the Novaya Zemlya fold‐and‐thrust belt represents the best provenance candidate for polycyclic components in Norian–Rhaetian strata. In addition to recycling in the hinterland during the Late Triassic, local erosion of exposed intrabasinal highs and platforms at the Triassic–Jurassic transition represents a second process where thermodynamically unstable mineral components originally sourced from the Uralides may be removed. Textural and mineralogical modification may also have occurred in marginal‐marine depositional environments during periods with elevated sea level. Mature sediment supply from the rejuvenated hinterland in the south, multiple cycles of reworking and gradual accumulation of polycyclic grains have likely led to the extreme compositional maturity registered in the Tubåen, Nordmela and Stø formations in the SWBSB. It is likely that increased annual precipitation since the latest Carnian had an amplifying effect on sandstone maturation across the Triassic–Jurassic boundary, but we consider the effect to be inferior compared to provenance shifts and reworking. Findings from this study are important for understanding compositional and textural maturity enhancement processes in siliciclastic sedimentary basins.

Diversity and preservation of Pleistocene tetrapods from caves of southwestern Bahia, Brazil

The study of two caves from the Serra do Ramalho region is here presented, this is one of the most important karstic areas in Brazil. A taxonomic analysis revealed 29 taxa including Xenarthra, Cetartiodactyla and Carnivora, ranging from Late Pleistocene to Early Holocene. Taphonomic studies reveal taphocoenosis consisting mainly of complete elements, without significant transportation, but also of transported elements, composing spatial-mixed, predominantly in situ-preserved assemblages. The predominance of Xenarthrans found within the caves is probably biased by a taphonomic pattern since these animals would have life habits related to cave environments, therefore with higher chances of preservation. There is evidence of accidental death of the scelidotheriines in Lapa dos Peixes cave, where entrapment of the animals during one or more events of river flooding is pointed as a hypothesis. Deposition took place within different periods of dry and humid climate incorporating bones in clastic and chemical deposits. Cycles of sedimentary deposition and reworking (erosion) may have acted in generating complex and overlapping depositional patterns with time averaging. During depositional phase, while the cave environment was occupied rather by Xenarthrans, parts of other animals were transported in the scope of fluvial systems and gravity loads, as well as by accidental falling or scavengers. The sedimentary deposits are currently being eroded by rain runoff in both caves, causing the reallocation of finer sediments to deeper conduits but the fossils keep close to their original location. This process is exposing a large amount of fossils, allowing extensive sampling which would be impossible with active excavations, since it would require an excessively longer time and damages to the caves.

Inventory decisions in a closed-loop supply chain system with learning and rework

In this study, we investigate a closed-loop supply chain model consisting of a manufacturer and a retailer. The retailer orders items from the manufacturer to satisfy the end customer's demand. The manufacturer uses both regular production and remanufacturing processes to produce items to fulfill the demand from the retailer. The returned items are collected and screened by the manufacturer for recovering process. We consider learning process in regular production and remanufacturing processes. In addition, the imperfect items produced during regular production are reworked. The model contributes to the current literature by allowing the inclusion of learning process in regular production and remanufacturing processes, imperfect items, rework and multiple cycle policy. Our objective is to optimise the percentage of the used item purchasing price per raw material cost, retailer ordering cycle, number of regular production cycles and the number of remanufacturing cycles, so that the joint expected total annual profit incurred has a minimum value. Furthermore, an algorithm is proposed to find the solutions of the proposed model. We also provide a numerical example and perform a sensitivity analysis to illustrate the model's behaviour and feasibility.

Software Engineering Methodology for Development of APIs for Network Management using the MEF LSO Framework

Standardized open APIs are a cornerstone of successful automation of intra- and inter-carrier telecommunication networks. MEF 55 defines an agile methodology that, with support of proper tool chaining, can deliver open APIs from an information model in an automated fashion. This methodology is an example of a spiral approach with feedback loops that enable quick rework cycles at each step of the process and help to maintain integrity between all artifacts that are produced. By using the MEF life cycle service orchestration (LSO) PRESTO reference point and MEF PRESTO network resource provisioning (NRP) API as a running example, we discuss the steps of the LSO engineering methodology and propose a tool chain that enables process automation.

Estimating Project Performance through a System Dynamics Learning Model

Monitoring of the technical progression of projects is highly difficult, especially for complex projects where the current state may be obscured by the use of traditional project metrics. Late detection of technical problems leads to high resolution costs and delayed delivery of projects. To counter this, we report on the development of a updated technical metrics process designed to help ensure the on-time delivery, to both cost and schedule, of high quality products by a U.K. Systems Engineering Company. Published best practice suggests the necessity of using planned parameter profiles crafted to support technical metrics; but these have proven difficult to create due to the variance in project types and noise within individual project systems. This paper presents research findings relevant to the creation of a model to help set valid planned parameter profiles for a diverse range of system engineering products; and in establishing how to help project users get meaningful use out of these planned parameter profiles. We present a solution using a System Dynamics SD model capable of generating suitable planned parameter profiles. The final validated and verified model overlays the idea of a learning S-curve abstraction onto a rework cycle system archetype. Once applied in SD this matched the mental models of experienced engineering managers within the company, and triangulates with validated empirical data from within the literature. This has delivered three key benefits in practice: the development of a heuristic for understanding the work flow within projects, as a result of the interaction between a project learning system and defect discovery; the ability to produce morphologically accurate performance baselines for metrics; and an approach for enabling teams to generate benefit from the model via the use of problem structuring methodology.

Investigating the Effect of Customization on Rework in a Higher Education Enterprise Resource Planning (ERP) Post-Implementation Environment: A System Dynamics Approach

Management of enterprise resource planning (ERP) projects is exceedingly challenging due to their large scope and complexity. Schedule and cost overruns have been widely reported in ERP implementation for years. Not only are resources critical to successful ERP implementation, but the post-implementation requires substantial resources as well. However, the resources required to maintain and extend ERP systems after implementation are not well understood, especially in the presence of software customizations which increase the total cost of ownership. This research applies system dynamics simulation modeling, focusing on the rework cycle, to data of a case study toward three primary goals. First, it contributes to both the system dynamics literature and the pre-packaged software literature by exploring the post-adoption ERP environment and extending the task rework cycle. Secondly, it develops a simulation model, grounded in ERP literature and in well-established system dynamics project models, helping practitioners and organizations in making more informed customization decisions by giving them a tool to better assess the long-term resource implications of ERP customization. Lastly, it addresses research gaps recently identified regarding issues such as customization, project evaluation, effort estimation, impact of adoption, system maintenance, performing updates with enterprise apps, and potential reasons for system abandonment.

A generalized duration forecasting model of test‐and‐fix cycles

ABSTRACTRework is inherent in product development, but estimation of the duration and required resources for rework cycles is inhibited by task size variation, process capacity variation, and the process characteristics of dynamism and concurrency. This difficulty is especially evident in testing of software‐intensive systems. Dynamic modeling of test‐and‐fix cycles has addressed this problem by providing good forecasting of test phase durations and by providing good results in supporting resource allocation and process improvement decisions. A generalized model of test‐and‐fix phases has been produced from an analysis of commonality and variation in six project models. The generalized model can be configured to support test phase planning of duration and resources. This paper extends the work reported in ICSSP 2012 by reporting results of experiments on managing test‐and‐fix projects through work‐in‐process limits and through test case prioritization. Copyright © 2014 John Wiley & Sons, Ltd.

Indo‐Antarctic derived detritus on the northern margin of Gondwana: evidence for continental‐scale sediment transport

AbstractProvenance studies from Cambro‐Ordovician sediments of the North Gondwana passive margin typically ascribe a North African source, a conclusion that cannot be reconciled with all observations. We present new U‐Pb ages from detrital rutile and zircon from Late Ordovician sediments from Saxo‐Thuringia, Germany. Detrital zircons yield age populations of 500–800 Ma, 900–1050 Ma and 1800–2600 Ma. The detrital rutile age spectra are unimodal with ages between 500 and 650 Ma and likely represent, together with the 500–800 Ma and 1800–2600 Ma zircon populations, detritus sourced predominantly from North Africa. In contrast, the c. 950 Ma zircons, which are persistently found in Cambro‐Ordovician sediments of North Gondwana, have no obvious African source. We propose that these zircons are sourced from the Rayner Complex–Eastern Ghats regions of Antarctica and India. An Indo‐Antarctic source indicates either continental‐scale sedimentary transport from central Gondwana to its peripheries or multiple cycles of sediment reworking and redeposition.

Effects of Multiple Reworks on the Accelerated Thermal Cycling and Shock Performance of Lead-Free BGA Assemblies

In this paper, the effect of multiple rework cycles (up to 5×) on reliability of lead-free assemblies is investigated. The test vehicle is designed to capture the reliability impact of rework processes on interconnects of ball grid array (BGA) devices, the solder joints of its adjacent components, and BGA devices of clamshelled devices. The effects on high aspect ratio plated through hole (PTH) vias and microvias are also considered. A variety of BGA packages, such as flip-chip BGA, plastic BGA, and chip array BGA are selected to represent different package technologies and stress levels. The effect of multiple reworks on the behavior of lead-free solder joints during accelerated thermal cycling (ATC) and mechanical shock is extensively explored in this paper. The experimental and analytical findings showed that multiple reworks significantly degraded the ATC performance of the reworked assemblies by up to 50% in terms of characteristic life. It is also found that multiple reworks affect the PTH vias significantly. The combination of increased lead-free rework temperature excursions and high-end printed circuit board (PCB) aspect ratios may incur higher stresses in the PTH copper barrel. Early failures are observed post multiple reworks and the subsequent ATC test due to PTH barrel cracking. However, the effects of multiple reworks are less severe for devices with microvias compared to those with PTH vias. Multiple reworks also cause severe degradation of long-term performance of devices with clamshell designs. With proper control in rework process, multiple reworks have minimum effects on the adjacent BGA solder joints. In addition, failure analysis is performed in order to study the impact of multiple rework on the microstructure of SnAgCu solder joints. It is found that the intermetallic compounds (IMC) layer grows thicker as the number of reworks increases; however, the IMC growth rate and morphology are dependent on the surface finish of the package substrate. The failure mode and failure mechanism after ATC are also compared for different number of rework cycles. The implications of these results for the reliability of lead-free solder joints are discussed in this paper.

Enhanced Rolled Throughput Yield: A new six sigma-based performance measure

Abstract The quality level measurement of a given process is essential to some phases of six sigma methodology. So far, different indicators have been applied to estimate the capabilities of a process such as classic yield, defect per unit, sigma quality level and rolled throughput yield. However, the examination of the efficiency of total processes in a certain organization is a recent challenge which is, unfortunately, not thoroughly explored in scarce studies undertaken. The proposed approach called Enhanced Rolled Throughput Yield (ERTY), unlike other methods, pays particular attention to such factors as the difference between scrap and rework cycles, the cost of scrap and rework and the sequence of stages. Moreover, the proposed approach is able to cover all previous methods. The presented real case illustrates the results of applying this model upon the industrial production of electronic sets.

A progression of induration in Medusae Fossae Formation transverse aeolian ridges: evidence for ancient aeolian bedforms and extensive reworking

ABSTRACTA progression of induration, erosion, and redeposition of transverse and networked transverse aeolian ridges (TARs) has been documented in the Medusae Fossae Formation (MFF), Mars. Cratered and eroded aeolian bedforms are rarely observed on Mars, indicating that those found in the MFF have been inactive for much longer than those found elsewhere. Indurated TARs are observed to grade into faceted MFF terrain, indicating a genetic relationship between the two. We propose that TAR deposition, induration and erosion have played a larger role in the surface morphology and evolution of the MFF than previously recognized. The deposition, induration, and erosion of TARs indicate that the MFF has undergone multiple cycles of reworking, and that much of its current surface morphology does not reflect the circumstances of its primary emplacement. Copyright © 2011 John Wiley & Sons, Ltd.

Multi-storey calcrete profiles developed during the initial stages of the configuration of the Ebro Basin's exorrheic fluvial network

Multi-storey calcrete profiles developed in the Quaternary on strath terraces of the Cinca and Alcanadre rivers, tributaries of the Ebro River in NE Spain. Two calcrete profiles (Tor 1 and Tor 2) near the village of El Tormillo show horizons with an arrangement that differs from that of commonly described calcrete profiles. Significant lateral changes occur in these profiles within a distance of less than 200 m, reflecting their pedofacies relationship. The Tor 1 profile on terrace Qt1 (the highest and oldest) consists of six horizons (from bottom to top): 1) coarse fluvial gravels; 2) mudstones with carbonate nodules; 3) a chalky horizon; 4) laminar horizons, including one peloidal horizon; 5) a multi-storey horizon formed of at least six minor sequences, each of which includes a lower detrital layer, a pisolithic horizon, and a thin discontinuous laminar horizon (these sequences indicate several cycles of brecciation and/or reworking); and 6) a topmost laminar and brecciated horizon also including reworked pisoliths. Some 200 m to the north of Tor 1, horizon 5 undergoes a lateral change to channel fill-deposits. The infill of the channels shows a fining-upwards sequence ranging from clasts of about 10 cm in diameter to red silts with sparse pebbles. All the clasts come from the underlying calcrete horizons. Laminar horizons are interbedded with the clastic channel deposits. The youngest calcrete profiles developed on terrace Qt3 of the Cinca River and on the Qp4 and Qp6 mantled pediment levels. All show relatively simple profiles composed mostly of lower horizons of coated gravels, with thin laminar horizons at the top. Most of the horizons, especially the laminar ones, show biogenic features such as alveolar septal structures, calcified filaments, biofilms, spherulites, micropores and needle-like calcite crystals. These features indicate the important role of vegetation in the formation of all the above profiles. The interbedding of clastic sediments and pisolithic horizons within the Tor 2 profile indicates several stages of stabilisation during profile formation. These sequences are an indication of the sedimentation, soil formation and reworking processes operating on the soil surface. The alternation of these processes is interpreted as the result of climate–vegetation changes. The channel-fills of Tor 2 indicate erosion and reworking of the hard laminar calcrete horizon. Both Tor 1 and Tor 2 are multi-storey profiles reflecting the complex sedimentation–erosion–pedogenesis relationships at the final stages of the development of its corresponding fluvial terrace. The study of these calcretes shows that these supposedly abandoned terraces continue to be active even though the fluvial network is entrenched. Both the pedofacies relationships and the complexity shown by Tor 1 and Tor 2 reflect the complex and unstable geomorphic setting in which these profiles developed. After the establishment of the exorrheic network, less complex calcrete profiles were produced in the lower terraces.

Procedure rework: a dynamic process with implications for the “rework cycle” and “disaster dynamics”

AbstractArchetypal dynamic structures link the behaviors of the diverse systems of interest to system dynamics modelers. In this article, dynamic behaviors of Procedure Rework processes—used in system operations to update procedures as they are invalidated by changes in the system state and its environment—are linked to two archetypal structures: the “rework cycle” and “disaster dynamics”. A case study focused on procedure rework in Space Shuttle Mission Control and involving the development of simulation models of procedure rework calibrated with data from five Space Shuttle missions is presented. A detrimental effect in the process—the rework propagation end‐of‐mission effect—is identified and linked to three general aspects of rework (rework time horizons, propagation of rework beyond the time horizons, and events forcing timely completion of all remaining rework) that may be improved upon in this and other rework processes. Furthermore, the effect's causes are characterized as examples of endogenous causal mechanisms for disaster dynamics. Copyright © 2011 System Dynamics Society.

An Empirical Study of Information Flows in Multidisciplinary Civil Engineering Design Teams using Lean Measures

Achieving smooth and continual flow of information among teams of independent designers is one of the central difficulties in detailed design of complex civil engineering projects. Lean production flow phenomena such as bottlenecks, rework, large batches and long cycle times are common. This research sought correlation between the degree of success achieved, in terms of design document effectiveness, meeting budget and schedule targets, and participant satisfaction, on the one hand, and the occurrence of information flow problems, on the other. Extensive data describing the communication of design documents between team members were collected in the detailed design phase of 14 civil engineering projects, all of which were part of a major airport construction project. The degree of effectiveness of the design documents, the extent to which budget and schedule targets were met, and participants' evaluations of their success were measured. The results confirm positive correlation between the quality of information flows and the effectiveness of design documents, and confirm that unstable information flows are associated with unpredictable project outcomes. No correlation was found between information flow problems and design managers' subjective views of the processes, nor between their performance evaluations and their fulfilment of budget or schedule targets.

Modeling the rework cycle: capturing multiple defects per task

AbstractThe rework cycle is at the heart of modeling projects, one of the major research and application areas in system dynamics. The current formulations for the rework cycle assume each task is either defective or not. Yet in many projects multiple defects can occur in one task. In this study we introduce a new rework cycle formulation that accounts for multiple defects per task and flexibly captures the testing process. We compare this formulation with two established formulations from the literature. Analysis shows some differences in simulated projects' finish time and delivered quality across different models and we discuss how these differences depend on project characteristics and task structure. The new formulation could be especially useful when data on tasks, defects, and testing have different measures, and when each new defect in a task significantly increases the chances of the task being rejected. Copyright © 2010 John Wiley & Sons, Ltd.