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  • 1.
    Bildsten, Louise
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Erikshammar, Jarkko
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Haller, Martin
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Värdeflödesanalys hjälper företag att korta ledtider, minska lager och ta bort slöseri2010Other (Other (popular science, discussion, etc.))
    Abstract [sv]

    Forskning vid Luleå tekniska universitet har visat på att Värdeflödesanalys (VFA) kan hjälpa företag att korta ledtider, minska lager och reducera slöseri genom att hitta en gemensam bild över företagets processer och fokusera mer på kundbehovet. En utvecklad arbetsmodell lyfter fram vikten av planering, ha rätt team och följa upp resultatet.

  • 2.
    Björnfot, Anders
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Bildsten, Louise
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Erikshammar, Jarkko
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Haller, Martin
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Simonsson, Peter
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Lessons learned from successful value stream mapping (VSM)2011In: Proceedings of IGLC-19: 19th Conference of the International Group for Lean Construction / [ed] John Rooke; Dave Bhargav, Lima: Fondo Ed. Pontificia Universidad Católica del Peru , 2011, p. 163-173Conference paper (Other academic)
    Abstract [en]

    To improve, it’s crucial to see! Vital characteristics of Lean are visualisation and transparency, i.e. allowing everyone to see all what occurs in production. A common tool for this purpose is Value Stream Mapping (VSM). Due to varying flows, performing a successful VSM in construction confers additional challenges. In this paper, lessons learned from successful VSM studies in construction are provided.Three VSM case studies were performed at different companies ranging from patio door manufacturing to kitchen cabinet assembly. Lessons learned can be structured into three phases; preparing the VSM (selecting “value stream leaders” and VSM team, clarifying values, etc.), performing the VSM (use of mapping tools, approximation of key indicators, waste identification, etc.), and following-up the VSM (Plan-Do-Check-Act, evaluating customer values, etc.).For the involved companies, the lessons learned imply the start of a “Lean journey” even though the involved companies found it difficult to relate VSM improvements to business strategies. Consequently, there are opportunities to further improve the application of VSM. However, it’s important to remember that VSM is about the straight-forward visualisation of flows and that these flows are made transparent for the whole organisation.

  • 3.
    Erikshammar, Jarkko
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Bildsten, Louise
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Haller, Martin
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Value Stream Mapping: a case study of an inner wall manufacturer2014Report (Other academic)
    Abstract [sv]

    Kartläggning av värdeflöden har blivit ett av de mer använda verktygen inom Lean sammanhang. Dessutom är det ett viktigt verktyg för ständiga förbättringar.Dess framgång är kopplat till skapandet av en stor visuell karta över hela företagets processer och samspelet mellan dessa processer. I arbetet med att göra kartan, fås en djupare kunskap om företaget genom att de som utför arbetet i processerna deltar i arbetet att rita upp värdeflödeskartan.Denna rapport är en fallstudie av Moelven Eurowand, en tillverkare av innerväggssystem för kontor. Syftet med studien var att undersöka möjligheterna att förkorta ledtiden för glasväggar. Företaget besöktes två gånger. Vid det första besöket genomfördes kartläggning av värdeflödet och vid det andra besöket skedde uppföljningen av kartläggningen. Företagets representanter uttryckte att värdeflödesanalysen var givande.

  • 4. Erikshammar, Jarkko
    et al.
    Engelmark, Henrik
    Haller, Martin
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Värdeflödesanalys: En pilotstudie på Finsnickeriet AB2010Report (Other academic)
    Abstract [en]

    The background to the report, written under the graduate course "Pilot study: Value Stream Analysis", is to assess the method of value stream mapping. The theory that has been used is from the field of Lean Production. The empirical data is gathered on Finsnickeriet in Råneå AB and the report is a case study of a specific product; the balcony door to Älvsbyhus. Data has been collected during two visits to Finsnickeriet and via phone and email. During visits, the interviews and the methodology of learning-to-see was used. The company's own time measurements for the different process steps have also been used. Improvement proposals suggest that the company should continue working on, good order, for example with 5S and marking of storage areas, changing the layout of the painting in order to create a cell, set up time reduction in the plane, and smaller batches whenever possible. We believe that Finsnickeriet must do so in small steps to reduce the risk.Report does not account for other activities such as order preparation, quality issues and affecting the overall result. The errors we are aware of the study is the uncertainty surrounding collection of the cycle and setup times

  • 5.
    Haller, Martin
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Critical design activities in house-building projects: an industrial process perspective2012Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    Dealing with planning accuracy respectively design errors is a big issue within construction. It has been argued that design errors are a major cause for waste in housing projects, despite all technical development. Reasons for design errors are well investigated and often relate to human acting. Because of the complex structure of the design process, i.e., the strong interrelation of the activities in the design phase, several activities have to be iterated if a design error at a certain activity occurs and is not detected immediately. Deviations from a planned sequence of activities, i.e., flow interruptions in Lean terminology, do not only imply rework but means also a higher risk for loosing control over the project. It can result in, e.g. poor coordination of project participants, necessary changes in schedules, possible time pressure to hold the schedule and about all a higher risk for making errors again.The long term goal of this research is to reduce cost variability of building projects by enhancing flow control in the design phase. A good flow control means to be able to carry out an activity sequence as planned. Existing literature mainly gives general, rather strategically advises what to do or not to do in order to enhance flow. But only few studies can be found dealing with the complex structure of the design process, enabling the development of concrete countermeasures at certain activities, e.g. placing checkpoints. The idea of this research is that not every faulty activity output will have the same effect on the flow in the design phase. The research question is how activities with a high impact on the flow in the design phase can be identified.A housing project was mapped in detail with focus on the activities carried out and theirs relations amongst each other in order to get a better understanding about the complexity of a building design process. The building is a two storey residential home with about 1100 m2. It is carried out in a new building system, a prefab system that is based on timber frame elements. The project was organised in an open building system and the project team consisted of around 10 contractors, small and medium sized enterprises from all over Sweden. An important postulate for this work is that, even there is a high variation of performance across projects, there is an underlying process structure, i.e. relations between the activities, which do not vary much for a certain building system. By applying design structure matrix algorithms a standard sequence of activities (reference process) has been derived. The execution of projects has been simulated via arbitrary deviations from the sequence, where a deviation had a certain consequence for the further proceeding because of the existing relations. The output variable of the simulation model is a measure for the occurrence of sequence deviations.The simulation result indicates that activities with a high number of subsequent activities with long working hours have a bigger influence on the flow in the design phase than activities that dominate only few activities with low working hours.

  • 6.
    Haller, Martin
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Design Iteration Control Framework for Offsite Building Projects2014Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    During the course of the studies this thesis is based upon a designiteration control framework for offsite building projects wasconceptualized. The ultimate goal was to develop a robust tool to assistproject managers to find the optimal balance between maintainingsufficient project-by-project iteration to solve complex designproblems, and avoiding excessive iteration, which unnecessarilycomplicates design and scheduling. In total three frameworkcomponents were developed. The thesis describes the problemaddressed, presents background information, describes the developmentof the framework components, and discusses their potential utility inconstruction contexts.Offsite building has been advocated as an effective means toincrease product quality while reducing project duration and cost,provided the design process is efficient. A main challenge in managingthe design process is iteration. It must be possible to alter details inorder to react to changes in conditions and meet project-specificrequirements, but unplanned design iteration should be avoidedbecause it can lead to departures from planned activity sequences,thereby increasing both scheduling and design complexity. In projectmanagement literature, two groups of approaches (system dynamic andmodel-based) for managing design have been established. The firstgroup is used to identify factors that affect design iteration and thusactions that could improve the process, while model-based approachesare used to investigate and predict possible effects of specific designiterations on project outcome. A problem is that current methods donot support attempts to quantify effects of specific improvementactions on project outcome, which could greatly facilitate effectivemanagement of resource-constrained projects.Due to the notion that all building projects are unique (which isprevalent in construction management literature) and the complexstructure of design processes, it is generally difficult to identify and mapiteration phases, cycles or loops in terms of specific actions.However, in offsite building projects it is reasonable to assume thatthe same design activities have to be carried out in all projects(regardless of the variation in their conditions), albeit to varying extentsand, furthermore, that the precedence relations between activities isinvariant. Thus, in this thesis (and the underlying studies) offsitebuilding design projects are considered as realizations of a process thatis characterized by varying activity extent but invariant precedencerelations.The suggested framework is a model-based continuousimprovement approach (plan-do-check-act cycle). Essentially it consistsof cycles of observing effects of applied actions over the course ofseveral projects, drawing inferences about the effectiveness of theactions from the observations, identifying improvements, applyingimproved actions and observing their effects. The frameworkincorporates techniques such as design structure matrix (DSM)-basedsimulation and Monte-Carlo inverse analysis. It comprises a method tocalibrate DSM-based simulation models, a relative measure of designiteration, and a method to identify the most critical process phases (interms of design iteration). The framework is mainly based on datarelated to the design process of a two-storey offsite timber framebuilding, supported by probability density functions for 35 other offsitetimber frame multi-storey building projects. The practical applicabilityof the framework components has been tested in simulationexperiments where they were applied to assess design processes relatedto this type of project, with variations in key conditions. To a lesserdegree the framework was also applied to a planning and buildingapproval process. The results of the simulations indicate that thecomponents have high potential practical applicability, providedaccurate records of activity execution sequences and correspondingwork amounts are available.

  • 7.
    Haller, Martin
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Lu, Weizhuo
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Stehn, Lars
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Jansson, Gustav
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    An indicator for superfluous iteration in offsite building design processes2015In: Architectural Engineering and Design Management, ISSN 1745-2007, E-ISSN 1752-7589, Vol. 11, no 5, p. 360-375Article in journal (Refereed)
    Abstract [en]

    Enhancement of iteration management in the design phase is important for successful offsite building projects. Design iteration has two aspects. Although iteration is necessary to deal with design requirements when solving complex problems (i.e. increasing quality through iteration), it has also been identified in numerous studies to be one of the main causes of design errors and time and cost overruns (i.e. superfluous iteration), as it increases scheduling and design complexity. Current building project management tools do not provide a means to control the reduction of superfluous iteration. One problem is that existing research has difficulty precisely relating the effects of specific management actions to superfluous iteration. The idea of this study is to develop an indicator, the sequence deviation quotient (SDQ), which reflects the amount of superfluous design iteration in a project. It can be thought of as a tool supporting project managers to make systematic and continuous (from project to project) design process improvement. A premise is that the impact of varying project conditions on the process structure of design processes, i.e. the precedence relationships between the design activities, is only small. In this paper, we provide a definition of superfluous iteration. We tested the feasibility of the SDQ by subjecting it to project variation and input perturbation by means of a Monte Carlo simulation. The simulations are based on the data from a real offsite design building process, the designing of a 1100 m2 residential building in Sweden.

  • 8.
    Haller, Martin
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Stehn, Lars
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Evaluation of efficiency in housing construction design2012In: ARCOM, twenty-seventh annual conference 2011, September 5-7, Bristol / [ed] Charles Egbu ; Eric Choen Weng Lou, Reading: Association of Researchers in Construction Management , 2012, Vol. 2, p. 797-806Conference paper (Refereed)
    Abstract [en]

    In housing projects a lot of time is spent for rework, entailing the risk of additional costs, time and deficient quality. As much as 50% or more of rework is originated in faulty output from the design phase. Activities within this phase are strongly interrelated and are carried out by several design consultants. Once the sequence of work in an ongoing project is interrupted the risk for loosing control is high. This results in, e.g., poor coordination of project participants, necessary changes in schedules, possible time pressure and about all a higher risk for making errors. The goal with this study is to reduce the risk of work sequence interruptions in the design phase of housing projects, or in terms of Lean, to make activities in the design phase flow. A timber housing multi dwelling building project in Sweden has been mapped in detail. In total 212 activities have been observed and recorded, spanning from the sales to the erection phase. Iterations (rework) have been identified by using process mining techniques in combination with supplemental interviews. A map of the complete design process consisting of 112 activities (exclusive of iteration) has been derived. A measurement model to detect process regions with a high share of iteration has been proposed that, together with the process map, serves as a starting point for further process optimisation. The efficiency of an activity is assessed by comparing the working hours, ignoring the time used for negative iteration (waste), with the working hours actually used to execute this activity. A Pareto-analysis of the occurring iteration with negative impact on quality then provides an indication of a suitable order for process optimisation.

  • 9.
    Haller, Martin
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Stehn, Lars
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Increasing the Accuracy of a Prefab Building Design Process Simulation Using Simulated Annealing2014In: Automation and robotics for construction: proceedings : CC2014 / [ed] Miklós Hajdu ; Mirosław J. Skibniewski, Budapest: Diamond Congress Ltd , 2014, p. 408-413Conference paper (Refereed)
  • 10.
    Haller, Martin
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Stehn, Lars
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Increasing the Accuracy of a Prefab Building Design Process Simulation Using Simulated Annealing2014In: Procedia Engineering, ISSN 1877-7058, E-ISSN 1877-7058, Vol. 85, p. 214-221Article in journal (Refereed)
    Abstract [en]

    Monte-Carlo simulation analysis has been discussed in project management literature as tool for proactive scheduling and to gain better insights into projects which are characterized by a high level of complexity and uncertainty, such as the design phase of prefab building projects. The application of simulation as proactive scheduling tool in construction projects is hampered by limited accessibility of proper input data, though, because of long project duration, the often temporary organization and multidisciplinary nature of such projects. In this study we use simulated annealing to adjust parameters of a simulation model for which the simulation outcome is sensitive to data perturbation by making use of data from related parameters which is easier to estimate. The applicability of the approach was demonstrated on a real life project, the construction of a 1100 m2 residential building in Sweden. More precisely, we used Design Structure Matrix simulation, i.e. an activity network based Monte-Carlo simulation technique with which stochastic project evolution (deviations from the planned activity sequence due to unexpected iteration of sub-processes) can be simulated, to model the workflow of the design process of the observed project. Then, by means of the simulated annealing approach, we adjusted the rework probabilities (model parameter) such that the frequencies of executed activities in simulated activity sequences fitted the frequencies as observed in the real project. Adjusting input data by using prior knowledge of the dependencies of the project activities and cross analysis with related data that is easy to estimate would help to increase the accuracy of simulations when access to statistical data of the input variable in question is limited. The suggested approach is interesting for practitioners who work with standardized design processes (e.g. as part of standardized building systems) and continuous improvement

  • 11.
    Haller, Martin
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Stehn, Lars
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Standardizing the pre-design-phase for improved efficiency in off-site housing projects2010In: ARCOM twenty-Sixth Annual Conference 2010, September 6-8, Leeds / [ed] Charles O. Egbu; Eric Lou, Reading: Association of Researchers in Construction Management , 2010, Vol. 2, p. 1259-68Conference paper (Refereed)
    Abstract [en]

    Long erection times on-site and project-specific design work, performed by consultants, generally accounts for a large part of correction and building costs in construction projects. In a typical Swedish housing project, the pre- and design phase accounts for about 10-12 % of the total costs. Due to a lack of standardized conceptualization procedures, much of the design work is reiterated in each project, and thus avoidable costs are incurred. In order to minimize these problems an open building system, called MFB, which exploits standardized technical solutions, design and construction processes for off-site prefabricated housing is under development. The MFB system developer will provide a process manual that describes, in detail, standardized design, construction, and erection processes. The open building system relies on close cooperation with local, often small to medium-sized, enterprises that can efficiently undertake “local” building projects. Here, we present and analyse a standard procedure for the pre-design-phase to incorporate in a MFB-process manual. The pre-design-phase of a MFB-building project was recorded and analysed in terms of efficiency. A detailed process map is presented, showing that 122 process steps were logged from the first contact with the client until the generation of the tender. By standardizing the pre-design-phase, the number of essential activities could be reduced by 47%. An improvement in time efficiency of the pre-design-phase with co-instantaneous generation of effective cost estimates should lead to lower building costs in general. Furthermore, by tightly standardizing and controlling the process, it should be possible to repeat projects (or many aspects of projects), without repeating much of the pre-design-phase, even if the actors change.

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