Sadi, Tarek, Wilberg, Julian, Tommelein, Iris D., and Lindemann, Udo (2016).
"Supporting the Design of Competitive Organizations by a Domain-specific Application Framework for the Viable Systems Model." The Journal of Modern Project Management (JMPM), September-December, pp. 103-109.
ABSTRACT: Industrial companies face the challenge of a rapidly changing environment and struggle to keep up with the pace needed to be competitive. Organizational deficiencies are often reasons for failure. The Viable System Model (VSM) supports organizational diagnosis and design to ensure viability and avoid deficiencies. The objective of this paper is to further support the application of the VSM in industry. Therefore, we conducted a literature review and analyzed twenty-five VSM case studies in order to derive a common application pattern. The results showed that the main assessment criterion was the existence of all VSM subsystems. However, interrelations within the VSM subsystems are often ignored. This paper presents an extended framework for applying the VSM, emphasizing subsystem relations when diagnosing as well as designing organizational systems. The extension is provided in the form of four Domain-Structure-Matrices, which reveal necessary interrelations and connections for a should-be organizational design.
Tommelein, Iris D. (2016).
"Teaching Lean Construction concepts with constructs modeled using discrete-event simulation."
Lean Construction Journal work in progress.
Thanopoulos, Theo, Tommelein, Iris D., and Ballard, Glenn (2015).
"Framework for Design Decision Making by 'Lean' Integrated Project Delivery Teams."
ASCE, Journal of Management in Engineering,
submitted in July 2013 and again in September 2015, in review.
ABSTRACT: Projects delivered by integrated teams (i.e., teams including owners, designers, contractors, and other trade partners) offer team participants the opportunity to collaboratively make design decisions in order to optimize the project as a whole. Such teams have to manage ever- increasing project complexity, stemming in part from increased use of building automation and rising performance expectations of buildings, driven by the desire to achieve sustainability values. In order to support team-based decision making, we here present a framework and design process methodology founded on Lean Construction principles (such as involving stakeholders early, establishing transparency, collaborating by sharing incomplete information often, considering sets of alternatives, making decisions based on facts, and deferring decision making to the Last Responsible Moment to support the team in making the best-informed decisions). Specifically, we describe the combination of Target Value Design (TVD) with Set-Based Design (SBD) and Choosing By Advantages (CBA). We use data excerpted from a case study to illustrate their use. Rigor in design process methodology, and training to effectively implement it, are needed by those who will be involved in Integrated Project Delivery (IPD) teams so that they will be able to develop shared understanding and collaboratively drive the delivery process toward achieving a shared goal. The framework and the supporting methodologies we present here offer a systematic approach to address a process challenge for integrated teams, for which few--if any--alternatives have been articulated and formalized to date.
Parrish, K., Wong, J.-M., and Tommelein, I.D. (2016).
"Set-based Design of Concrete Reinforcing Steel with BIM Support."
ASCE Journal of Construction Engineering and Management,
submitted for review on 29 May 2016, COENG-5326.
ABSTRACT: Today’s methods used when designing, detailing, and fabricating reinforcing steel (rebar) for concrete structures tend to be point-based. We herein present an alternative method, one that is set-based. Set-based design enables the exploration of feasible solutions for longer in the design process than is otherwise affordable using point-based design, thereby allowing for input from multiple project delivery team members simultaneously, from early design onwards. In support of the set-based method for rebar design, we deliver proof-of-concept by showing how the so-named SetPlan computer-based tool leverages Building Information Modeling software (in this case, Tekla Structures) to display design information in a dashboard format, so that the project delivery team can select a design solution that is satisfactory for all, though possibly not optimal for anyone. This paper also explores the need for and feasibility of implementing tools like SetPlan in practice.
Arroyo, P., Tommelein, I.D., Ballard, G., and Rumsey, P. (2015).
"Choosing By Advantages: A Case Study for Selecting an HVAC System for a Net Zero Energy Museum."
Energy and Buildings, 1 January 2016, 111:26–36, DOI:10.1016/j.enbuild.2015.10.023
ABSTRACT: Choosing a building system is not an easy task, especially when designers are concerned about the socialand environmental impacts of their choices, as in the case of a net zero energy (NZE) building. In addition,economic constraints are commonly misunderstood so that all too often decisions are based on what is cheaper upfront and do not take the life-cycle cost into account. Moreover, the interaction with increasing numbers of stakeholders makes decision-making even more complex. While decisions can be supportedby decision-making methods, in practice many are made without a formal method or discussion, which often generates conflict and waste in the design process. Few designers know how to incorporate social,environmental and economical factors when making a decision. This research fills the literature gap and provides practical advice for practitioners by demonstrating the application of a method called choosing by advantages (CBA) in order to create transparent and collaborative environments in which to make decisions. This paper presents a detailed case study of choosing an HVAC system for a NZE building in California. It provides evidence that CBA supports the choosing problem by integrating multiple perspectives, creating transparency, separating "value" from cost, and clearly documenting the decision rationale.
Arroyo, P., Tommelein, I.D., and Ballard, G. (2015).
"Selecting Globally Sustainable Materials: A Case Study Using Choosing By Advantages."
ASCE, Journal of Construction Engineering and Management, 2016, 142(2): 05015015
DOI: 10.1061/(ASCE)CO.1943-7862.0001041.
ABSTRACT: Design teams must make hundreds of decisions in building design, including choosing materials. Lately, they have become more concerned about the social and environmental impacts of their choices, in addition to the economic constraints. These concerns, in addition to the increasing offerings of construction materials and products and the engagement of more stakeholders, make decisions more complex. As decision complexity increases, so does the need to systematically use sound decision- making methods. However, many decisions in practice are made without a formal method or discussion, thereby often generating conflict and waste in the design process. Further, even if practitioners are looking for better decision making methods, the literature does not provide enough support for them to select the best method for this context. This research fills the literature gap and provides a systematic approach as well as practical advice for decision makers by demonstrating the application of a method, called Choosing By Advantages (CBA). CBA creates transparent and collaborative environments in which to make decisions. To illustrate the use of CBA, this paper provides a detailed example of choosing materials, in this case ceiling tiles, in a commercial interior design project considering global supply chain issues. This paper provides evidence that CBA (1) supports the material choice problem, (2) integrates multiple perspectives, (3) keeps decisions linked to the context, (4) creates transparency, (5) builds a collaborative environment, (6) separates “value” and cost, and (7) provides a clear manner of documenting rational decisions. CBA is a method worth adding to the tool box of design teams determined to select globally sustainable materials.
Steinhaeusser, Tobias, Elezi, Fatos, Tommelein, Iris D., and Lindemann, Udo (2015).
"
Management Cybernetics as a Theoretical Basis for Lean Construction Thinking."
Lean Construction Journal, pp. 1-14.
ABSTRACT:
Question: Management
cybernetics claims that any successful organization responds to its laws. As there are numerous
successful enterprises that use lean thinking as a management philosophy, including increasing
numbers of construction companies, does this claim hold and if so, do these laws offer the
opportunity to sharpen understanding of lean construction practices?
Purpose: The purpose of
this paper is to explore the use of management cybernetics—specifically Stafford Beer’s Viable
Systems Model—as a theoretical basis for lean construction thinking. Research Method: Review,
analyze, and compare literature on management cybernetics and lean construction. Develop an example
to illustrate such use.
Findings: Through a theoretical approach of describing lean thinking
rules from the perspective of management cybernetics, we were able to show that following this
argumentation, the lean construction idea of Built-in Quality (BiQ) fulfills all requirements of a
viable system in management cybernetics.
Limitations: Only a small selection of rules is analyzed in this paper.
Implications: Management cybernetics can help sharpen understanding
when implementing lean thinking in an industrial context. It may also help identify new concepts
that can be incorporated into lean thinking. Conversely, understanding lean thinking principles from
the perspective of management cybernetics may also help to identify problems where the
implementation of lean thinking does not live up to the desired results. However, further
exploration of these potential implications is required.
Value for authors: Introduce management cybernetics to the lean construction community in order to support lean systems thinking and spur interest in using the Viable Systems Model when diagnosing lean practices.
Keywords: Lean Construction, Lean Thinking, Theory, Built-in Quality (BiQ), Management
Cybernetics, Viable System Model (ViSM).
-
Tommelein, I.D. (2015).
"
Journey toward Lean Construction: Pursuing a Paradigm Shift in the AEC Industry."
ASCE, Journal of Construction Engineering and Management,
DOI: 10.1061/(ASCE)CO.1943-7862.0000926.
ABSTRACT:
This paper presents a personal historic view on lean construction, referring to the application of lean thinking to the delivery of capital projects in the architecture-engineering-construction (AEC) industry. Lean construction has caused a paradigm shift: it offers a new way of thinking to those involved in designing and managing AEC projects. The systems thinking that lean promotes began to develop in the AEC industry 20-some years ago and was spurred by the recognition that the then-current thinking about the delivery of projects was incongruent in many ways. The writer first offers conceptual underpinnings to frame this new way of thinking, and then describes her journey of discovery of incongruences in construction project management theory and practice. Along the way, the writer offers several partial yet complementary definitions of lean construction while giving examples and illustrations of the underlying lean thinking. The writer’s thesis is that lean thinking helps eliminate much self-inflicted, unwanted complexity from systems, so that people can accomplish more using simpler systems. Readers may not necessarily agree with this thesis, but are challenged to at least consider that lean thinking offers a new paradigm for the AEC industry, and that it is worth pursuing.
Hamzeh, Farook R., Saab, Issa, Tommelein, Iris D., and Ballard, Glenn (2014).
"
Understanding the Role of 'Tasks Anticipated' in Lookahead Planning through Simulation."
Automation in Construction, 49 (2015) 18-26, DOI: 10.1016/j.autcon.2014.09.005
ABSTRACT: Construction planning takes place at many levels. This paper pertains to the level called lookahead planning, during which planners make their plan more realistic as construction tasks approach execution. To improve the quality of lookahead planning, the construction industry has benefited from implementing the Last Planner(R) System (LPS) that emphasizes creating reliable workflow. Successful lookahead planning relies on task anticipation by breaking down tasks to the level of operations, designing those operations, and making tasks ready by identifying and removing their constraints so that tasks can become executable assignments. This paper presents a study, using computer simulation, of the relationship between improving Task Anticipated (TA) in lookahead planning and overall project duration. The results indicate that increasing TA can have a positive influence on reducing project duration. The authors recommend that industry practitioners use the TA metric to gauge their planning performance and then to improve on it.
Arroyo, P., Tommelein, I.D., and Ballard, G. (2014).
"
Comparing AHP and CBA as Decision Methods to Resolve the Choosing Problem in Detailed Design."
ASCE, Journal of Construction Engineering and Management, 141 (1) January 2015,
DOI: 10.1061/(ASCE)CO.1943-7862.0000915.
ABSTRACT: Multicriteria decision-making (MCDM) methods can help designers address the choosing problem in building detailed design. Many, however, appear to assume that all methods are equivalent. This paper argues that differences between MCDM methods matter. The first contribution of this paper is differentiating between the analytical hierarchy process (AHP) and choosing by advantages (CBA) by comparing them through an example. The second contribution is explaining why CBA is superior to AHP for this context. In summary, CBA (1) provides a more context-based analysis than AHP, (2) does not incorporate conflicting judgments for weighing factors as AHP does, (3) does not assume linear trade-offs between factors as AHP does, (4) does not assume that factors have zero as a natural scale as AHP does, (5) focuses on differentiating between alternatives more than AHP, (6) maintains the result of the decision when nondifferentiating factors are removed, whereas AHP may not, and (7) defers subjective judgments until late in the decision-making process, whereas AHP requires expressing them earlier. This presents a significant research finding, considering the wide use of AHP. Further research is needed to assess what range of design decisions CBA supports.
Lee, H.W., Tommelein, I.D., and Ballard, G. (2013).
"
Target Setting Practice for Loans for Commercial Energy-Retrofit Projects."
ASCE, Journal of Management in Engineering,
DOI 10.1061/(ASCE)ME.1943-5479.0000245, 04014046.
ABSTRACT: Current practices in commercial loan underwriting appear to lack depth in analysis, and appear weak in evaluating energy-related risks. Consequently, they raise financial barriers to energy efficiency (EE) investments. In response, we suggest a target setting practice that borrowers and lenders collaboratively can use during the early stages of an energy retrofit project. The practice uses a simulation called Energy Retrofit Loan Analysis Model (ERLAM) to determine the target building performance and the allowable cost for design and construction. Using a case study of an energy retrofit project, this paper demonstrates use of ERLAM by evaluating the impact of two identified energy-related uncertainties (project cost uncertainty and operational practice uncertainty) on the financial performance of the investment. This target setting practice can help project parties gain greater understandings and early confidence in the feasible size- and terms of a loan before moving to design development. As a result, the practice can support commercial underwriting by helping to overcome financial barriers to energy retrofit projects.
Lee, H.W., Tommelein, I.D., and Ballard, G. (2013).
"
Energy-related Risk Management in Integrated Project Delivery."
ASCE, Journal of Construction Engineering and Management, Special Issue on Sustainability,
published online in June, Dec 2013, Vol. 139, No. 12.
DOI 10.1061/(ASCE)CO.1943-7862.0000753
ABSTRACT: Developing energy efficient commercial buildings requires an energy-related risk management practice that can increase the chance of achieving intended lifecycle financial goals. This paper suggests a management practice that deals with such energy-related risks, namely, project cost risk and performance risk. A prerequisite to applying the suggested management practice is a high level of collaboration among different disciplines during design development as promoted, for example, when using integrated project delivery (IPD). As a case study to validate the management practice, this paper presents a California hospital project where the unique features of IPD helped the project team apply the management practice in the course of managing the energy-related uncertainties of an energy-efficiency measure. This paper illustrates the detailed design decision- making process of the team that used Target Value Design, the lean design management method. As a contribution to the body of knowledge, the purposes of this study are to present the case study that serves to validate the suggested practice and to show that the IPD application contributed to the capability and effectiveness of the practice in increasing the reliability of achieving the target lifecycle financial values while reducing system complexity and overdesign.
Ballard, G. and Tommelein, I.D. (2012).
"Lean Management Methods for Complex Projects."
Engineering Project Organization Journal (TEPO), Taylor & Francis, 2:1-2, 85-96.
ABSTRACT: This paper reviews the principles, history, applications and current research issues associated with lean construction, in order to provide a foundation for future research in this area. Lean is a management approach that emerged in the automobile industry and spread initially to other forms of repetitive manufacturing and ultimately to service industries. Despite its success in practice, the lean philosophy and methods have not been fully evaluated and incorporated into the academic literature. The question remains to what extent lean management methods are unique and beneficial and how they are related to principles and models in management science, production management and related fields. One of the relevant issues is the adequacy of lean methods to the management of complex projects. As project complexity increases, emergent phenomena increase. Consequently, leadership must become more adaptive and less prescriptive in order to be successful. This paper describes some of the key lean management methods that deliver better outcomes on complex projects and also the interdependence of these methods with the structuring of commercial terms and organizational integration. It also describes the relationship between lean project management methods and conventional methods, and the limitations of both, and suggests directions for future research.
Reijula, J. and Tommelein, I.D. (2012).
"
Lean hospitals: a new challenge for facility designers."
Intelligent Buildings International,
pp. 1-18, DOI: 10.1080/17508975.2012.680429
ABSTRACT: This article presents a literature review of a wide array of implementation studies of Lean healthcare practices, performed worldwide. First, we review some fundamentals of Lean thinking. Second, we describe the continuous work improvement cycle along with some commonly used Lean tools. We then examine how the implementation of Lean practices has affected hospitals and their users. Furthermore, we review the encountered challenges and opportunities. Finally, we present process- and technology improvement ideas to address the urgent needs and critical shortcomings of current healthcare practices. Lean practices are becoming increasingly widespread in the healthcare industry. Readers new to them might like to investigate their applicability more deeply.
Hamzeh, F.R., Ballard, G., and Tommelein, I.D. (2012).
"
Rethinking Lookahead Planning to Optimize Construction Workflow."
Lean Construction Journal, 2012 Issue, Paper 2, pp. 15-34.
ABSTRACT:
Research Question: How to improve lookahead planning practices in the construction industry to increase the reliability of weekly work planning?
Purpose: To present a framework to standardize lookahead planning practices, assess the performance of lookahead planning, and improve the reliability of production planning.
Research Design/Method: This study employs case study analysis, industry interviews, and an industry survey to assess the current implementation of lookahead planning on construction projects in North America, South America, and Europe.
Findings: The study findings indicate the existence of non-compliance with Last Planner(R) system rules, inadequate lookahead planning practices due to lack of standardized planning processes, sluggish identification and removal of constraints, and absence of analysis for plan failures.
Limitations: The authors' active role on the projects used as case studies may constitute a limitation to the research methods and tools used. The industry survey may have not covered all companies applying the Last Planner(R) system.
Implications: This research provides a framework for applying the Last Planner(R) system rules during lookahead planning. It aims at increasing the success of the making activities ready, designing operations, and ultimately improving PPC.
Value for practitioners: The study presents to industry practitioners applying the Last Planner(R) system a standardized framework for implementing lookahead planning on construction projects. The paper also highlights the use of two metrics to assess the performance of lookahead planning at a given point in time and to monitor performance over a period of time or between projects.
Lee, H.W., Tommelein, I.D., and Ballard, G. (2012).
"
Design of a design-build infrastructure project using a point-based methodology."
ASCE, Journal of Management in Engineering, 28 (3) 291-299,
DOI 10.1061/(ASCE)ME.1943-5479.0000103.
ABSTRACT: Our experience in engineering education and practice indicates that methodologies for architecture, engineering, and construction (AEC) design management are characterized only to a limited extent. In domains other than AEC such methodologies are well-established and contribute to improving design performance. A step towards advancing AEC design management is to characterize design practices and explore the methodologies on which they may be based. In this vein, the authors describe a design practice observed while participating in the development of a design-build-operate-and-maintain (DBOM) proposal for an infrastructure megaproject. The development team’s design process followed a point-based methodology, i.e., early selection from a small set of design alternatives. The team was structured as a three-party joint venture, but, as observed, integration of efforts and collaboration among its design engineers and contractors were difficult and infrequent. The point-based design methodology used showed limitations. The authors counterpose methodologies including select-and-reuse or set-based design. Especially the latter is worth adopting in our AEC industry because it has resulted in superior design performance in other domains. By characterizing and documenting a design management methodology used in practice and counterposing alternatives, the authors aim to spur discussion on the teaching and practical application of AEC design management methodologies.
Howell, G.A., Ballard, G., and Tommelein, I. (2011).
"
Construction Engineering: Reinvigorating the Discipline."
ASCE, Journal of Construction Engineering and Management, October, 137 (10) 740-744,
DOI: 10.1061/%28ASCE%29CO.1943-7862.0000276.
ABSTRACT: Construction Engineering is all about production and producing something useful is the very reason for projects to exist. How then to explain why Construction Engineering has progressively fallen out of focus in construction project management education and research? For an answer, we must understand the development of the discipline of construction management since the 1950s, a development that yielded a non-production-oriented approach to project management, one that provides the currently accepted operating system for managing the work in projects. This paper first traces the history of the development of the traditional operating system and related commercial terms and organizational practices. It argues that traditional practices rest on an assumption that careful development of a project schedule, managing the critical path and maximizing productivity within each activity will optimize project delivery in terms of cost and duration. Subsequently, we describe an alternative operating system, developed and proposed by the Lean Construction community. In contrast to the traditional approach, lean defers detailed planning until closer to the point of action, involves those who are to do the work in designing the production system and planning how to do it; aims to maximize project performance (not the pieces), and exploits breakdowns as opportunities for learning. The history of this development will be traced in broad strokes.
Nguyen, H.V., B. Lostuvali and I.D. Tommelein (2010).
"
A3: Decision Analysis Using Virtual First-Run Study of a Viscous Damping Wall System."
Lean Construction Journal pp. 99-101.
Tuholski, S.J. and Tommelein, I.D. (2010).
"
Design Structure Matrix Implementation on a Seismic Retrofit."
ASCE, Journal of Management in Engineering
(http://jrnmeeng.edmgr.com/), July, 26 (3) 144-152,
DOI: 10.1061/(ASCE)ME.1943-5479.0000016.
ABSTRACT: A void exists in development of design theory methodology (DTM) within the structural engineering (SE) community. This void hampers efforts to resolve performance deficiencies including cost over-runs, unplanned rework, and sub-optimal design. In manufacturing, product design and production improvements have resulted from implementation of the Design Structure Matrix (DSM) methodology. DSM offers a means to represent, analyse, and decompose complex systems in order to improve their performance. DSM use within the architecture engineering construction (AEC) industry has been sporadic and focused primarily in the UK. Where applied, DSM has proven effective at helping AEC design teams streamline processes to address non-linearity (non-sequential information flows) introduced by iteration and complexity in design. When a DSM reveals iteration and highly dependent work, group brainstorming, collocated design sessions, rapid feedback, set-based design, and collaborative design aids can be used to increase overall team effectiveness. This paper examines a case study where DSM-based planning software was used on a seismic retrofit project to drive process improvement in design management. DSM correctly identified iterative activities central to design and provided the following; 1) a common vocabulary to discuss rework in the context of a multi-disciplinary design team, 2) a rational method to schedule team collocation and brainstorming efforts to maximize their benefit, and 3) a means to consider iterative activities (and associated hand-offs) in design work structuring.
Milberg, C.T. and Tommelein, I.D. (2010).
"
Tolerance and Constructability of Soldier Piles in Slurry Walls."
ASCE, Journal of Performance for Constructed Facilities,
March/April, 24 (2) 120-127, DOI: 10.1061/(ASCE)CF.1943-5509.0000079.
ABSTRACT: Process capability (PC) characterizes the variation in a parameter of a process's output. From a constructability perspective, investigating PCs for geometric variation is important when specifying tolerances for all construction processes. This paper investigates a case involving soldier piles used in a slurry wall and compares the design specified tolerances to as-built field data. As with other cases investigated by the authors covering many major construction processes, this case also shows that designers specify tolerances based on tacit estimates of variation limits, not PCs. Consequently, the PCs consistently exceed the design specified tolerances, preventing the possibility of proper tolerance management and causing problems to manifest during construction. The authors conclude that variation estimates are an inaccurate basis for specifying tolerances and instead should be based on PCs.
Tuholski , S.J., Gursel , A.P., Tommelein, I.D., and Bomba, G. (2009).
"
'Lean' Comparison using Process Charts of Complex Seismic Retrofit Projects."
ASCE, J. of Constr. Engrg. and Mgmt., April, 135 (4) 330-339, DOI: 10.1061/(ASCE)0733-9364(2009)135:4(330).
ABSTRACT: This paper compares the delivery of two retrofit
projects where seismic isolation bearings were installed. The comparison is retrospective. The design teams on these
projects did not implement 'lean' thinking to develop their approach, nevertheless, observed process differences are
characterized using a 'lean' process evaluation and optimization tool, and then gauged and rationalized from that
perspective. Cross-functional process charts identify functional parties with interrelated material or information hand-
offs. They help to identify (un)necessary steps or complexity as measured by number of hand-offs and interacting
parties. Analysis of these charts shows that project value may stem from the owner integrating design development with
product procurement and construction method selection. On one project, integration was made possible by structural
engineers evaluating the impacts of product procurement on overall project performance, expert consultants providing
construction process reviews, and experienced contractors participating in installation sequence development. This paper
illustrates the value of developing a symbiotic relationship between designers and suppliers in a niche market. It
stresses the need for work structuring early on in the delivery process, integrating process with product development,
to improve project delivery.
-
Gil, N., Beckman, S., and Tommelein, I.D. (2008).
"
Problem-Solving Base Building under Uncertainty and Ambiguity: A
Multiple-Case Study on an Airport Expansion Program."
ASCE, J. of Constr. Engrg. and Mgmt., CO/2006/023664, 134 (12)
991-1001 (December), DOI: 10.1061/(ASCE)0733-9364(2008)134:12(991).
ABSTRACT: This multiple-case study induces alternative
strategies to coordinate the overlap of tasks to detail and physically execute base-building with tasks to conceptualize
the business-critical fit-out. Base-building subsystems provide service space for occupancy, whereas fit-out subsystems
make the space functional. Our empirical findings on problem-solving base-building design under uncertainty and
ambiguity stem from a number of projects in an airport expansion program. They suggest that base-building subsystems
show low sensitivity to incremental changes in fit-out as their definitions are seldom optimized to eliminate slack.
Yet, base-building subsystems show high sensitivity to radical changes in fit-out when the architectures of the two
subsystems are integral to one another. Three strategies for problem-solving base-building stand out: (1) iterate design
when preliminary information about fit-out is ambiguous, or precise but unstable; (2) physically decouple the
architectures of base-building and fit-out; and (3) design buffers in base-building when preliminary information about
fit-out lacks precision but it is not ambiguous. These buffers can be designed out if uncertainties in fit-out resolve
favourably before starting the physical execution for base-building.
Gil, N., Beckman, S., and Tommelein, I. (2008).
"
Upstream Problem-Solving under Uncertainty and Ambiguity: Evidence from Airport
Expansion Projects." IEEE Transactions on Engineering Management ,
DOI: 10.1109/TEM.2008.922635, published online as of 10 June 2008
ABSTRACT: Environmental changes are common during development of
large engineering (infrastructure) projects. To accommodate them when they occur, developers design and physically
execute the upstream base building with preliminary information about the downstream business-critical fit-out. Base-
building subsystems provide service space for occupancy, whereas fit-out subsystems make the space functional. We build
theory on design under uncertainty and ambiguity from case study research, drawing on theory of preliminary information
exchange in concurrent development. We find that the base-building subsystem shows low sensitivity to incremental
changes in fit-out. However, it shows high sensitivity to radical changes, unless the two subsystems interact in a
modular fashion. In the face of slow resolution of downstream uncertainty and difficulties in decoupling the physical
interfaces (as is the case in modular design for example), upstream developers avoid starvation by making working
assumptions at risk and exploring the space of possible design solutions through an early "optioneering" stage. Two
patterns for problem-solving upstream stand out: 1) iterate design when preliminary information is either ambiguous or
precise, but unstable and 2) build buffers in the design definition to absorb foreseeable changes when the preliminary
information lacks precision but is not ambiguous. Buffers can be designed out if downstream uncertainties resolve
favorably before the buffers are physically executed.
-
Alves, T. da C.L. and
Tommelein, I.D. (2007). "Cadeias de
suprimentos na construção civil:
análise
e simulação computacional." (original is in
Portugese, title in English is "Construction supply chains: analysis
and computational simulation.") Ambiente Construído,
Porto Alegre, 7
(2) 31-44, abr./jun. ISSN 1678-8621; available online at "
PDF
ABSTRACT: This paper discusses the importance of managing supply chains in the construction industry as well as concepts that may contribute for the improvement of their performance. In order to illustrate the concepts discussed and their importance, the authors present a simulation model developed using data from the HVAC sheet metal ductwork supply chain. Conducting experiments on supply chains can be rather costly and time consuming. Therefore, simulation tools can be employed to carry out low cost studies of supply chains. Those tools can be used for generating models that mimic a controlled environment in which experiments can be carried out. Four scenarios were studied to evaluate the impact that variations on activity durations and batching have on the project lead time. The conclusions highlight the use of simulation as a tool for supply chain and production system design, the need to improve communication channels between different parts of the supply chain aiming to reduce inventories, and the impact that variability and batching have on the project lead time.
RESUMO: Este artigo discute a importância do gerenciamento da cadeia de suprimentos da construção civil bem como conceitos que podem contribuir para a melhoria de seu desempenho. De modo a ilustrar os conceitos discutidos e a sua relevância para o tema, as autoras apresentam um modelo de simulação desenvolvido com base em dados da cadeia de suprimentos de dutos de ar-condicionado. Experimentos com cadeias de suprimentos podem demandar muito tempo e esforço para serem realizados. Dessa forma, a simulação computacional tem grande potencial para o estudo de cadeias de suprimentos, pois pode ser empregada com baixo custo e gerar modelos e conclusões que representem uma realidade controlada na qual experimentos podem ser realizados. Quatro cenários foram simulados para avaliar o impacto que variações nas durações das atividades da cadeia de suprimentos e a definição de grandes lotes têm no tempo de entrega (lead time) de um projeto. Como conclusões, destacam-se o uso de simulação computacional para o projeto de sistemas produtivos e cadeias de suprimentos, a necessidade de melhorar a comunicação entre partes da cadeia como forma de reduzir seus estoques, e o aumento do tempo de entrega do projeto à medida que a variabilidade das durações e o tamanho do lote aumentam.
-
Gil, N., Tommelein, I.D.,
and Schruben, L.W. (2006).
"External Change in Large Engineering Design Projects: The Role of the
Client." "IEEE
Transactions on Engineering Management, 53 (3)
426-439, August.
ABSTRACT: A problem facing the management of large engineering projects is: Why do clients often adopt an early commitment strategy on design decision-making when they want to speed up project delivery, yet allow late changes to the project definition to accommodate the resolution of (un)foreseen external uncertainties? Empirical findings illustrate this problem and underpin a 2-stage model of the concept development process, in which conceptualization is followed by design, and stochastic pre-emption simulates asymmetric changes. Simulation experiments demonstrate that when clients make commitments early in conditions of high uncertainty, they increase the likelihood (upside risk) of speeding up the delivery if external events do not materialize; however, if these events do materialize, they increase the likelihood (downside risk) of causing design rework and losing process predictability— especially when the ability to reuse design work after a change is limited. We show that moderate design postponement is appropriate if clients strategically relinquish some of the upside risk of finishing the project sooner. Moderate design postponement does not increase the downside risk of overrunning the project completion date in relation to the risk clients incur when they commit earlier because it reduces expected variability in design. These insights highlight the client’s role in foreseeing external uncertainties and judiciously instructing changes to design teams. They also demonstrate the applicability of postponement to large engineering design projects where external uncertainty emerges as a fundamental contingency.
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Elfving, J.A., Tommelein, I.D., and Ballard, G. (2005).
"Consequences of Competitive Bidding in Project Based Production."
"Journal
of Purchasing and Supply Management, 11:173-181.
ABSTRACT: This paper discusses the consequences competitive bidding have on lead time in project-based production, such as construction. Earlier studies argued that competitive bidding may significantly increase resource consumption and generate waste in the delivery process, which this paper supports. However, the relation between competitive bidding and lead time has been less discussed. Lead time reduction has long been considered a fundamental objective for overall business improvement. An objective of our study was to understand what contributes to long lead times. The reported findings are from a 4-year study on the delivery process of power distribution equipment, a type of engineered-to-order (ETO) product. The paper concludes by suggesting procurement practices that reduce lead times for ETO products.
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Gil, N., Tommelein, I.D., Stout, A., and Garrett, T. (2005).
"Embodying
Product and Process Flexibility to Cope with Challenging Project
Deliveries." ASCE, Journal of Construction
Engineering and Management, 131 (4) 439–448, April.
ABSTRACT: Four factors make it challenging to manage semiconductor fabrication facility ("fabs") projects: technical complexity of the product design, need to compress the project duration, need to reduce upfront costs, and unexpected project changes. The strategies employed by practitioners to cope with these challenges form an intricate puzzle. We empirically develop a framework that provides a structure for helping to solve this puzzle, which comprises two principles: investing upfront in a flexible product design and structuring a flexible process. Empirical findings reveal that project teams make commitments early on by overdesigning but also postpone critical decisions by differentiating the scope of their work. Project teams employ other strategies such as increasing communication, using modular architectures, engaging in four-dimensional computer-based modeling, and fabricating components and subsystems off-site. Our analysis yields understanding on the purposes and performance tradeoffs of these strategies, and on how they embody the two principles. Project managers may find the framework useful when deciding which strategies best suit other equally challenging projects.
Gil, N., Tommelein, I.D.,
and Beckman, S. (2004). "Postponing
Design Processes in Unpredictable Environments." Research
in Engineering Design, 15 (3) 139-154, December.
ABSTRACT: This work explores the effectiveness of design postponement in the concept development phase of large-scale engineering projects. Our empirical research shows limited use of postponement in semiconductor fabrication facility (fab) projects despite evidence that the customer inevitably requests design criteria changes in the projects life. We simulate fab concept development as a 2-stage process—conceptualization followed by design. We find that postponing the start of design in relation to the completion of conceptualization reduces the average resources spent on design and the variability in the concept development duration but increases the average concept development duration. A sensitivity analysis on the postponement lag duration indicates, however, that some degree of postponement may allow reducing design rework without increasing the risk of overrunning the project completion date, in comparison to the risk with early commitment. Further, simulation indicates that the effectiveness of postponement decreases as designers' capability to reuse work increases.
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Tsao, C.C.Y., Tommelein,
I.D., Swanlund,
E., and Howell, G.A. (2004). "Work
Structuring to Achieve Integrated Product-Process Design."
ASCE, J. of Constr. Engrg. and Mgmt., Nov/Dec, 130
(6) 780-789.
ABSTRACT: This paper presents "work structuring," a term used to describe the effort of integrating product and process design throughout the project development process. To illustrate current work structuring practice, we describe a case study involving the installation of door frames into walls in a prison. We analyze why various problems existed. To improve the work structuring effort, we apply the "five whys" to develop local and global fixes for the system of precast walls and door frames. The five whys is a technique to elicit alternative ways of structuring work without being constrained by contractual agreements, traditions, or trade boundaries. We discuss the importance of dimensional tolerances in construction and how these affect the handoff of work from one group of workers to the next. We argue that these constraints and tolerance management practices are so embedded that project participants can miss opportunities to better integrate product and process design. We propose shifting the focus of work structuring from maximizing local trade efficiency to improving overall performance in the delivery system of a capital project.
- Tsao, C.C.Y., Tommelein, I.D., Swanlund, E., and
Howell, G.A. (2006a). "Work Structuring to Achieve Integrated
Product-Process Design, Part I." Doors and Hardware, June,
pp. 42-48.
- Tsao, C.C.Y., Tommelein, I.D., Swanlund, E., and
Howell, G.A. (2006b). "Work Structuring to Achieve Integrated
Product-Process Design, Part II." Doors and Hardware, July,
pp. 32-44 and 77.
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Walsh, K.D., Hershauer, J.C., Tommelein, I.D., and Walsh, T.A. (2004).
"
Strategic Positioning of Inventory to Match Demand in a Capital Projects Supply Chain."
ASCE, J. of Constr. Engrg. and Mgmt., Nov/Dec, 130 (6) 818-826,
DOI: 10.1061/(ASCE)0733-9364(2004)130:6(818)
ABSTRACT: Industrial buyers of capital facilities have experienced and continue to experience pressure to reduce facility design and construction lead time. This pressure arises both internally (due to successes in manufacturing lead time reductions) and externally (due to competitive forces including narrowing product delivery windows). This paper presents a case study detailing one owner's efforts to reduce the length and variability of delivery time for long-lead construction materials in order to improve overall project lead time. The owner adopted a long-term multiproject perspective, procuring material in advance of specific projects and holding it at a position in the supply chain selected to allow flexibility for customization. Reduction in lead time of 75% from order to delivery of the material resulted for individual projects within the owner's capital plan. As a result, the material was available at the construction site well in advance of its need for erection. To study if holding material at alternative locations in the supply chain could provide a better match between delivery quantities and the demand for erection, the supply chain was simulated. In this case study, demand information was imprecise, allowing only the quantity of material delivered to be considered rather than matching specific items to specific locations. Nonetheless, the results demonstrate the utility of simulation in the capital projects supply chain and the value of improving demand forecasts.
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Gil, N., Tommelein, I.D., and Ballard, G. (2004).
"Theoretical Comparison of Alternative Delivery Systems for Projects in Unpredictable Environments."
Construction Management and Economics, 22 (5) 495-508, June.
ABSTRACT: A project delivery process simulation is presented based upon empirical studies in the design-build environment of semiconductor fabrication facilities ('fabs'). The model captures key tasks and decisions in design, procurement and construction, as well as design criteria changes along the delivery of a R&D fab utility system. Simulation shows that to involve the specialty contractor from the project start on average expedites project delivery since it prevents delays caused by bidding and by contractors' unfamiliarity with the design product definition. Yet, in unpredictable project environments - environments in which design criteria are likely to change irrespectively of the project progress status - simulation reveals that the averages of construction rework and waste increase if design is prematurely frozen. Assuming that work methods do not change and design criteria remain uncertain, results indicate that a system that combines early contractor involvement with judicious postponement of the design start reduces the average duration of the fab utility delivery in relation to the expected duration if competitive bidding was used, with limited increase in the averages of construction rework and waste. Additional efficiency is gained when specialty contractors relax conservative assumptions on anticipated site conditions. An economic model uses simulation results to assess the tradeoffs between alternative project delivery systems for the case of R&D fabs.
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Choo, H.J., Hammond, J., Tommelein, I.D., Austin, S., and Ballard, G. (2004).
"DePlan: Tool for Integrated Design Management." Automation in Construction, 13 (3) 313-326, May.
ABSTRACT: The iterative and information-intensive nature of the design process makes it hard to plan and schedule work using tools for conventional project management. The success of design projects depends on the quality of the available information. This paper proposes DePlan as a method for integrated design management during the detail design phase. DePlan integrates two techniques, namely ADePT and planning according to Last Planner™, each involving a software tool. ADePT implements the dependency structure matrix analysis method to identify iterative processes and the planning strategy for managing them. Planning according to Last Planner™ follows a production management philosophy that includes reliably scheduling and controlling design activities. Combined as DePlan, these techniques help planners generate quality plans, i.e., plans that express what is ready for execution by sequencing activities in the right order, identifying informational and resource requirements ahead of design execution, and by scheduling only activities that have met these requirements. This collaborative research has successfully developed the DePlan approach and associated computer software and tested them.
-
Dzeng,
R.-J.
and Tommelein, I.D.
(2004). "Product Modeling to Support Case-based Construction Planning
and Scheduling."
Automation in Construction, 13 (3) 341-360, May.
ABSTRACT: Many
human schedulers create schedules by reusing past similar schedules.
The retrieval and reuse of similar schedules are subjective and experience-based. This paper explores different notions of similarity required when performing different scheduling tasks. It describes the CasePlan system that helps schedulers retrieve and reuse parts of existing schedules based on a generic product model, and apply case-based reasoning to generate new schedules. The validation experiment demonstrated CasePlan’s accuracy in determining individual subnetworks and activity durations, but weak performance in determining interlinks between subnetworks, which highly depends upon the availability of pertinent cases and the level of detail of project information.
-
Arbulu, R.J., Tommelein, I.D., Walsh, K.D., and Hershauer, J.C. (2003).
"Value Stream Analysis of a Re-engineered Construction Supply Chain."
J. Building Research and Information
- Special Issue on Re-engineering Construction, Spon
Press, 31 (2) 161-171.
ABSTRACT: A study is presented that documents the most common configuration of the supply chain for pipe supports used in power plants in the USA. This supply chain, like many others in construction, has numerous inefficiencies, many of which occur at the interfaces between processes, disciplines or organizations. Recognizing and understanding such inefficiencies, their causes and potential remedies provides a basis for process re-engineering. The study describes how today's industry practices are changing to yield shorter supply chain lead times. To model the mechanisms that drive those changes, data are presented from industry practice in the form of value stream maps that span across organizational disciplines and company boundaries. Metrics commonly used in lean construction are introduced to gauge system performance. A current state map documents how work flows throughout the design, procurement and fabrication phases of pipe supports. Analysis of this current state map highlights value-added and non-value-added times and lead times. A future state map then illustrates process improvements that can be obtained by applying various supply chain management tactics. The methodology applied in this study could be applied to other construction supply chains equally well.
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Whelton, M., Ballard, G., and Tommelein, I.D. (2002).
"A Knowledge Management Framework for Project Definition."
ITcon, Special Issue ICT for Knowledge Management in Construction, Vol. 7, pp.
197-212.
ABSTRACT: This paper proposes a knowledge management framework for project definition of capital facility projects. The conceptual framework emphasizes project-based learning and the creation of group knowledge in early phase project planning and design activity. The use of multi-disciplinary expertise in this phase of project development acknowledges the use of multiple decision frames by which stakeholders approach project solutions. This research views project definition as a collaborative decision-making process, and highlights the need for supporting group management techniques and technologies. Project definition is regarded as the phase of project development where exploration of alternatives creates innovative problem and solution definitions that allows maximum customer value generation to be developed. This paper proposes a management framework to support organizational and process interfaces within project definition. The model is based primarily on findings from recent research literature and on exploratory descriptive research. The model presents a process for project definition and supports group knowledge creation and management. The model bases its development on soft systems methodology to support group cognition, learning and creative solution generation. Collaborative group theory is incorporated into the model to support project definition. The framework builds on theoretical principles of lean design and construction.
-
Gil, N., Tommelein, I. D., Kirkendall, R.L., and Ballard, G. (2001).
"Leveraging Specialty-Contractor Knowledge in Design-Build Organizations." "Engineering,
Construction, and Architectural Management (ECAM),
October/December, 8 (5/6) 355-367.
ABSTRACT: Specialty contractors have knowledge to contribute to the early design of architecture, engineering, and construction (AEC) products. In current practice, however, they are seldom involved in early design, but evidence suggests that their early involvement is increasing. Lean construction theory advocates such involvement. The practice of involving suppliers in product development efforts and manufacturing has proven to be highly successful. The paper reports on empirical research that identified the contributions of specialty contractor knowledge to early design, which led to gains in process efficiency and improvements in product quality. These contributions are categorized and illustrated by means of examples that stem from current practice or present potential opportunities for improvement. Reasons are given why specialty contractor knowledge is often ignored in design. Changes in AEC practices nevertheless suggest that organizations are creating conditions to increase interaction between designers and specialty contractors. Such interactions will help AEC organizations to retain and share the knowledge of individuals as well as learn to develop new knowledge.
Zouein, P.P. and Tommelein, I.D. (2001).
"
Improvement Algorithm for Limited Space Scheduling." ASCE, J. of Constr. Engrg. and Mgmt., 127 (2) 116-124, March/April,
DOI: 10.1061/(ASCE)0733-9364(2001)127:2(116).
ABSTRACT: Selecting construction methods and scheduling activities along with planning the use of site space over time are key to constructing a project efficiently. Site layout and activity scheduling have traditionally been tackled as independent problems. Their interdependence is often ignored at the planning stage and may be dealt with-if at all-when construction is underway. Problems that may have had easy solutions if dealt with earlier, may then be expensive to remedy. This paper addresses the combined problem termed "space scheduling" and presents an algorithmic time-space trade-off model for adjusting activity durations and start dates to decrease the need for space over congested time periods. The model characterizes resource space requirements over time and establishes a time-space relationship for each activity in the schedule based on minimum, normal, and maximum resource levels. An example illustrates the presented algorithm that generates a feasible space schedule.
Zouein, P.P. and Tommelein, I.D. (1999).
"
Dynamic Layout Planning Using a Hybrid Incremental Solution Method."
ASCE, J. of Constr. Engrg. and Mgmt., 125 (6) 400-408, Nov/Dec, DOI: 10.1061/(ASCE)0733-9364(1999)125:6(400).
ABSTRACT: Efficiently using site space to accommodate resources throughout the duration of a construction project is a critical problem. It is termed the "dynamic layout planning" problem. Solving it involves creating a sequence of layouts that span the entire project duration, given resources, the timing of their presence on site, their changing demand for space over time, constraints on their location, and costs for their relocation. A dynamic layout construction procedure is presented here. Construction resources, represented as rectangles, are subjected to two-dimensional geometric constraints on relative locations. The objective is to allocate site space to all resources so that no spatial conflicts arise, while keeping distance-based adjacency and relocation costs minimal. The solution is constructed stepwise for consecutive time frames. For each resource, selected heuristically one at a time, constraint satisfaction is used to compute sets of feasible positions. Subsequently, a linear program is solved to find the optimal position for each resource so as to minimize all costs. The resulting sequence of layouts is suboptimal in terms of the stated global objective, but the algorithm helps the layout planner explore better alternative solutions.
Tommelein, I.D., Riley, D., and Howell, G.A. (1999).
"
Parade Game: Impact of Work Flow Variability on Trade Performance."
ASCE, J. of Constr. Engrg. and Mgmt., 125 (5) 304-310, Sept/Oct, DOI: 10.1061/(ASCE)0733-9364(1999)125:5(304)
ABSTRACT: The Parade Game illustrates what impact work flow variability has on the performance of construction trades and their successors. The game consists of simulating a construction process in which resources produced by one trade are prerequisite to work by the next trade. Production-level detail, describing resources being passed from one trade to the next, illustrates that throughput will be reduced, project completion delayed, and waste increased by variations in flow. The game shows that it is possible to reduce waste and shorten project duration by improving the reliability of work flow between trades. Basic production management concepts are thus applied to construction management. They highlight two shortcomings of using CPM for field-level planning: CPM makes modeling the dependence of ongoing activities between trades or with operations unwieldy and it does not explicitly represent reliability. The Parade Game can be played in a classroom setting either by hand or using a computer. Computer simulation enables students to experiment with numerous alternatives in order to sharpen their intuition regarding variability, process throughput, buffers, productivity, and crew sizing. Managers interested in schedule compression will benefit from understanding work flow variability’s impact on succeeding trade performance.
-
Tommelein, I.D. (1999). "Lean Construction Experiments
using Discrete-event Simulation: Techniques and Tools for Process
Re-engineering?" International Journal of Computer-Integrated
Design and Construction, CIDAC, Special issue on Construction
Process Re-engineering, 1 (2) 53-63, September.
ABSTRACT: The construction community concerned with process re-engineering needs formal techniques and modeling tools to support their efforts. This paper proposes that lean construction, a theory of production custom-tailored to suit the needs of construction, be embraced to drive re-engineering efforts. Several lean production techniques have already been adapted successfully to address construction needs. This paper specifically provides an example that illustrates a lean technique called ‘pulling.’ It also shows how computer-based discrete-event simulation can be used as a tool to model and experiment with alternative production systems, in order to study their characteristic properties such as buffer sizes and production rates. The provided example pertains to supply-chain materials-management in industrial construction. The systematic application of a production theory combined with computer experimentation prior to field implementation of a re-engineered system is bound to increase its likelihood of success.
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Choo, H.J., Tommelein, I.D., Ballard, G., and Zabelle, T.R. (1999).
"
WorkPlan: Constraint-based Database for Work Package Scheduling."
ASCE, J. of Constr. Engrg. and Mgmt., 125 (3) 151-160, DOI: 10.1061/(ASCE)0733-9364(1999)125:3(151).
ABSTRACT: A database program called WorkPlan has been created to systematically develop weekly work plans. Such work plans are used by crew foremen in scheduling work packages and allocating available labor and equipment resources. WorkPlan adopts the Last Planner methodology, which implements several lean construction techniques. A week prior to conducting work, WorkPlan guides the user step by step through the process of spelling out work packages, identifying constraints, checking constraint satisfaction, releasing work packages, and allocating resources; then at the end of the week, collecting field progress data and reasons for plan failure. This systematic approach helps the user create quality work plans and learn from understanding reasons for failure. The lean planning philosophy underlying WorkPlan and the functionality of the computer program implementation are detailed in this paper. Various ways of displaying work package data are illustrated. WorkPlan's job-shop scheduling view complements the view traditionally adopted by project management, as is reflected in scheduling tools using the critical path method (CPM).
-
Tommelein, I.D. (1998).
"
Pull-driven Scheduling for Pipe-Spool Installation: Simulation of Lean Construction Technique."
ASCE, J. of Constr. Engrg. and Mgmt., 124 (4)
279-288.
ABSTRACT: Many construction processes include installation of unique materials in specific locations in the facility being built: materials and locations must match before installation can take place. Mismatches due to delay and uncertainty in supplying materials or completing prerequisite work at those locations hamper field productivity. This is illustrated here using a model of a materials-management process with a matching problem that typifies fast-track process-plant projects. The uniqueness of materials and locations combined with the unpredictability in duration and variation in execution quality of various steps in the supply chain allow for different ways to sequence material delivery and work area completion. Several alternatives are described. Their impact on process execution is illustrated by means of probabilistic process models. One model reflects total lack of coordination between delivery and work area completion prior to the start of construction; a second one describes perfect coordination. The corresponding materials staging buffers and construction progress are plotted based on output from discrete-event simulation models. A third probabilistic model then illustrates the use of the lean construction technique called pull-driven scheduling. Real-time feedback regarding the status of progress on site is provided to the fabricator off site so process steps can be re-sequenced opportunistically. This yields smaller buffers and earlier project completion and, when properly accounted for, increased productivity.
The Stroboscope source code file 'PipeSpool.STR'of the pipe-spool model described in this paper is available for download by clicking "here. Please acknowledge the source when using this model in or as a basis for your work. You will need to get the "STROBOSCOPE simulation engine to run this code.
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Dzeng, R.J. and Tommelein, I.D. (1997).
"Boiler Erection Scheduling Using Product Models and Case-based Reasoning."
ASCE, J. of Constr. Engrg. and Mgmt., 123 (3) 338-347.
ABSTRACT: Contractors who repeatedly construct facilities designed by copying major parts from one project to the next find that previously developed schedules associated with those designs could be reused to schedule new work. To facilitate such reuse, project characteristics must be articulated and associated schedules described to include not only traditional, numerical scheduling data, but also scheduling constraints. In addition, knowledge about how to reuse schedules must be available. The CasePlan system, presented here, supports and augments the scheduling activity of people who reason about cases—each case describing the design and schedule of a completed project—to generate new project schedules. Specifically, CasePlan reuses annotated cases to automatically schedule the erection of power plant boilers. Because such boilers have a more-or-less standardized design, a generic boiler product model can serve as the basis for assessing similarities between designs. On this basis CasePlan selects schedules for reuse. A user can also interact with CasePlan to isolate fragments of case schedules and adapt them to better suit the variables of the new project at hand.
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Tommelein, I.D., Carr, R.I., and Odeh, A.M. (1994). "Assembly of Simulation Networks using Designs, Plans, and Methods."ASCE, J. of Constr. Engrg. and Mgmt., 120 (4) 796-815.
ABSTRACT: An object-oriented and interactive computer system is presented that realistically models construction processes by matching resource properties with design component properties and operation durations. This system, named CIPROS, uses a modular representation to create discrete-event simulation networks, and to aid in relating simulation output back to the design and construction plan of a facility to be built. CIPROS users must identify and describe attributes of components to be constructed, based on the facility's design drawings and specifications, and they must develop a critical path method (CPM) plan. They must also select a construction method to perform each activity by retrieving the appropriate elemental simulation network from a library of networks that represent such methods. CIPROS then pieces together the networks based on sequential relationships from the plan and property values input from the drawing and specification data. The latter initialize the simulation network resources that make up the constructed facility. To complete the simulation network, users must specify the construction resources that are available to perform the work and which may be shared by activities. CIPROS comprises a fully operational discrete-event simulation engine that is called once a network is completed. Besides producing statistical reports that are instrumental in assessing the quality of the construction plan, CIPROS can also be used to check the degree of facility completion as the simulation progresses.
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Balkany, A., Birmingham, W.P., Maxim, B.R., Runkel, J.T., and Tommelein, I.D. (1994). "DIDS: Rapidly Prototyping Configuration Design Systems." Journal of Intelligent Manufacturing, (5) 33-45.
ABSTRACT: This paper describes an object-oriented system, known as the Domain-Independent Design System (DIDS), for rapidly constructing design tools. DIDS supports a graphic-based development paradigm, where a tool builder assembles a design tool from a library of reusable software objects called mechanisms. Once configured, these objects are automatically converted to C++ code that implements the design system. This paper explores the issues involved in constructing DIDS, particularly the definition of objects to ensure that they capture the proper level of functionality and can be easily combined. An example of DIDS constructing a bicycle configuration system is given.
Tommelein, I.D. and Zouein, P.P. (1993).
"Interactive Dynamic Layout Planning."
ASCE, J. of Constr. Engrg. and Mgmt., 119 (2) 266-287, http://dx.doi.org/10.1061/(ASCE)0733-9364(1993)119:2(266)
ABSTRACT: The layout of temporary facilities on a construction site necessarily changes over time, so the term dynamic layout is used to describe a sequence of layouts spanning the entire duration of construction of a project. Many layout changes are dictated by the construction schedule. In the MovePlan model, which is presented here, the activity schedule is therefore augmented with data needed to construct layouts, i.e., resources required to perform activities, and their dimensions. This augmented schedule can drive the dynamic layout process, including the positioning of temporary facilities on site and the movement of materials and equipment. Conservative modeling assumptions were made in order to keep computational costs low, so that the MovePlan implementation would run on a microcomputer and thus be readily field‐usable. The MovePlan prototype system provides a graphical interactive interface with underlying consistency maintenance mechanisms. MovePlan enables users to model approximate site space needs during project scheduling and to create layouts for different stages of construction. Several strategies for creating layouts are described. MovePlan's output can be further refined by adding geometric detail and using more sophisticated graphical packages for detailed process planning. MovePlan can also be integrated with off‐the‐shelf project‐management software.
Balkany, A., Birmingham, W. P., and Tommelein, I.D. (1993). "An Analysis of Several Design
Systems." Artificial Intelligence for Engineering, Design, Analysis and Manufacturing, AI EDAM, 7 (1) 1-17,
DOI: http://dx.doi.org/10.1017/S0890060400000032
ABSTRACT: Design has been extensively studied by artificial intelligence researchers for many years. These studies have resulted in a large number of design tools that perform interesting tasks. Understanding the capabilities of these tools is, however, very difficult, which seriously impedes progress in the field. A better understanding of different tools can be achieved by analyzing the knowledge use of existing tools. Such an analysis of six configuration design tools is presented. This results in a model of configuration design that shows significant similarity in the tasks performed by these tools.
Tommelein, I.D., Hayes-Roth, B., and Levitt, R.E. (1992). "Altering the SightPlan Knowledge-based Systems." J. of Artificial Intell. in Engrg., Design, and Mfrg., AI EDAM, 6 (1) 19-37,
DOI: http://dx.doi.org/10.1017/S0890060400002924
ABSTRACT: SightPlan refers to several knowledge-based systems that address construction site layout. Five different versions were implemented and their components of expertise are described here. These systems are alterations of one another, differing either in the problems they solve, the problem-solving methods they apply, or the tasks they address. Because they share either control knowledge, domain concepts, or heuristics, and such knowledge is implemented in well-defined modular knowledge bases, these systems could easily re-use parts of one another. Experiments like those presented here may clarify the role played by different types of knowledge during problem solving, enabling researchers to gain a broader understanding of the generality of the domain and task knowledge that is embedded in KBSs and of the power of their systems.
-
Tommelein, I.D., Levitt, R.E., and Hayes-Roth, B. (1992). "SightPlan
Model for Site Layout." ASCE, J. of Constr. Engrg. and Mgmt., 118 (4) 749-766.
ABSTRACT: A model that uses artificial intelligence programming techniques is presented as a new tool for layout designers. This model, named SightPlan, represents the layout process as well as the layout product. A description of the knowledge and problem-solving method is given of the SightPlan system that mimics the actions of a human layout designer. SightPlan lays out temporary facilities, represented as rectangles, on a construction site, represented as a two-dimensional space. An early-commitment strategy and spatial constraint satisfaction techniques are used to find unique positions for facilities among those already in place. An example run in which SightPlan is applied to a case-study project illustrates how the program operates in stand-alone mode. SightPlan demonstrates that knowledge-based systems can successfully address problems not adequately modeled until now and, thus, opens up a new way of thinking about computer-aided decision support for the construction industry. The present system is a prototype, however. Additional work must be done before SightPlan will be ready for field use and useful to field practitioners.
-
Tommelein, I.D., Levitt, R.E., and Hayes-Roth, B. (1992).
"Site Layout Modeling: How Can Artificial Intelligence Help?"
ASCE, J. of Constr. Engrg. and Mgmt., 118 (3) 594-611.
ABSTRACT: A model that uses artificial intelligence programming techniques is presented as a new tool for layout designers. This model, named SightPlan, represents the layout process as well as the layout product. A description of the knowledge and problem-solving method is given of the SightPlan system that mimics the actions of a human layout designer. SightPlan lays out temporary facilities, represented as rectangles, on a construction site, represented as a two-dimensional space. An early-commitment strategy and spatial constraint satisfaction techniques are used to find unique positions for facilities among those already in place. An example run in which SightPlan is applied to a case-study project illustrates how the program operates in stand-alone mode. SightPlan demonstrates that knowledge-based systems can successfully address problems not adequately modeled until now and, thus, opens up a new way of thinking about computer-aided decision support for the construction industry. The present system is a prototype, however. Additional work must be done before SightPlan will be ready for field use and useful to field practitioners.
-
Tommelein, I.D., Levitt,
R.E., Hayes-Roth, B., and Confrey,
T. (1991). "SightPlan
Experiments: Alternate Strategies for Site Layout Design." ASCE, J.
of Computing in Civil Engrg., 5 (1) 42-63, Jan.
ABSTRACT: SightPlan is a knowledge-based system that lays out temporary facilities on construction sites. Its implementation architecture calls for explicit representation of the problem-solving strategy used to construct a solution layout. Because this strategy can easily be modified we explore several alternate formulations. This paper describes the development and testing of strategies that two agents might adopt to match their cognitive capabilities. One strategy models the steps taken by a construction manager laying out the site; it reflects human cognitive strengths and weaknesses. Recognizing that such a strategy would not be well-suited for execution by a computer, we critique it, and craft a second strategy to make better use of the computer's storage and computational capabilities. Although more powerful in several ways, this second strategy falls short of some human strengths, such as the ability to discriminate between alternatives. After comparing these two strategies, we develop a third, combining human and machine strengths. This strategy augments the second strategy with graphics to allow for human-computer interaction. We argue that the resulting joint cognitive system can generate better solutions than either a person or a machine.
