Defining VisiLean Requirements Framework

Following  key  aspects  emerge  from  the  study  of  literature,  which  are  shown  in   Table   18.   These   aspects   along   with   feedback   capture   from   practitioners   are   taken  into  consideration  while  designing  VisiLean.  

Table  18.  Defining  VisiLean  requirements.  

Requirement Discussion

Process and product

visualisation at the “coal face”

This is one of the most significant and overlapping requirement that emerges from past research (and also from prior case studies and exploration of the problem area). This means that the information regarding the planning and scheduling, along with the relevant design information (that forms the product model) should be made available to workers (construction team) on site.

Supporting

constraints analysis and management

This is also an essential requirement for a production management system and an aspect that is often neglected in most current systems. The system should allow the teams to identify, analyse and assign constraints. Once assigned the system should also allow tracking the status of the constraints linked to the tasks. Finally, analysis in the efficiency of removal of constraints should also be facilitated.

Supporting

collaboration, work negotiation and communication between the project team

Addressing people issues, building trust, improving coordination and communication and securing commitment to the production plan are some of the most critical issues that a new system has to address. All previous research initiatives recognise this aspect and put forward collaboration as a key requirement for a production planning system. Collaboration spans the entire lifecycle of the project, starting from lean work structuring and continuing to look-ahead planning, weekly commitment planning and daily execution, feedback and coordination (including start-stop signals).

The other key aspect to be recognised is that the production management process is a highly people centric and the goal of the computerised system should be to support the collaboration rather than automate the process. Many previous attempts have failed where the users have been alienated from the system due to high level of automation or the complicated nature of the system.

Enable “pull” flow control and plan stability

From lean perspective, “pull” production management is a key to reduce variability, which is one of the biggest enemies causing waste and uncertainty on construction. All previous researchers have identified the need for the system to support a combination of “push” and “pull” techniques to maintain plan stability and reduce variability. As can be observed in Table 13, the system should support the workflow starting from Master Planning and Phase Planning going on to Look-ahead plan and then weekly planning and daily execution. During this process the key aspect is that the system enables the users to create a workable backlog of constraint free tasks, which can be selected based on their priorities to improve flow and reduce work in progress, while also supporting coordination by signalling to downstream crew when the preceding task is completed.

Koskela  (2000)  presents  the  TFV  (Transformation,  Flow  and  Value)  framework   to   tackle   production   in   construction.   He   claims   that   all   these   three   conceptualizations  of  production  are  necessary  and  that  they  should  be  utilized   simultaneously.   This   is   one   of   the   most   fundamental,   theoretical   frameworks   from   lean   perspective   that   the   VisiLean   system   should   address.   Table   19   describes   the   specific   features   within   VisiLean   that   address   the   TFV   requirements.  

Table  19.  Addressing  TFV  through  VisiLean.  

VisiLean

Features Transformation Flow Value

Planning and

Scheduling Task Planning, and Scheduling- in Phase, Lookahead and Weekly Planning (software) interfaces help to maintain consistency in task specification.

Managing the flow of resources through constraints analysis and management. Assigning constraints to tasks and also the responsibility to manage them to workers and teams.

Reduction in making-do through improved performance of constraints removal process, leading to better performing planning and scheduling system leading to sounder tasks, less rework and better quality.

Task

Management Assigning completion task responsibility at the Last Planner level to workers.

To make input flows visible through linking of constraints to tasks (and their current status). Simultaneous Visualisation of process and product Visualisation of task information in process and model views, i.e. where and when the task is supposed to be executed.

Managing the flow of work between long term, medium term and short term planning processes.

Reduction of confusion through joint appraisal of production plan in both process and product views, improving the quality of work and reducing risk of rework and delays due to misunderstandings.

Production

Control Production features of starting, control stopping and completing tasks and their visualisation in both the model and process views. Managing and visualising in process flow between production tasks by Visualisation of task statuses in both product and process views.

Visibility of upstream task completion to downstream stakeholders.

One  of  the  requirements  put  forward  by  Sacks  et  al.  (2009)  is  that  of  maturity   and  pull  flow  index.  Although  providing  construction  teams  an  indication  of  the  

task   maturity   based   on   the   status   of   the   constraint   seems   beneficial,   the   associated  risk  regarding  the  accuracy  is  too  great  for  it  to  be  considered  viable.   As   a   construction   project   is   a   highly   dynamic   requirement   and   availability   of   resources  change  constantly  the  construction  managers  and  trades  foreman  are   the  best  judge  when  it  comes  to  making  decisions  regarding  resource  availability,   and  the  final  decision  is  best  left  for  a  human  to  make  rather  than  a  computer.   The  same  applies  for  the  “pull  flow”  index  as  it  depends  on  the  maturity  index   along  with  the  status  of  connected  tasks.  As  a  result,  these  two  features  were  not   implemented  in  VisiLean.  

Also,  majority  of  the  systems  discussed  above  did  not  put  forward  a  requirement   for   information   sources   to   be   aggregated   in   the   production   system   so   that   the   information   availability   at   the   decision   making   point   is   improved.   For   example   information   about   various   resources   could   reside   in   information   systems   belonging   to   main   contractor,   subcontractor   or   other   stakeholders.   Traditional   methods  for  integration  of  these  information  sources  have  been  through  direct   links  established  between  these  systems,  and  as  a  result  are  seldom  established.   This  leaves  the  production  management  system  isolated  from  other  information   sources.   Therefore,   this   is   considered   to   an   important   requirement   and   is   addressed   using   a   distributed   web-­‐services   framework   that   will   discussed   further  below.