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Claims  |
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We claim:
1. A method to aid graphically the management of a set of tasks, comprising
the steps of
representing a quantity associated with each task by a geometric object of
at least two dimensions whose geometric area or volume is indicative of
said quantity,
displaying each said geometric object on a display device, and
graphically indicating information about dependencies in the performance of
said tasks on said display.
2. A method to aid graphically the management of a set of tasks, comprising
the steps of
representing a quantity associated with each task by a geometric object of
at least two dimensions whose geometric area or volume is indicative of
said quantity,
displaying each said geometric object on a display device, and
graphically indicating information about dependencies in the performance of
said tasks on said display, including indicating spatial independence
between said tasks performed at spatially distinct locations.
3. A method to aid graphically the management of a set of tasks, comprising
the steps of
representing a quantity associated with each task by a geometric object of
at least two dimensions whose geometric area or volume is indicative of
said quantity,
displaying each said geometric object on a display device,
graphically indicating information about dependencies in the performance of
said tasks on said display,
associating a set of said objects representing related tasks at a first
level of said project together on said display device, and
generating an object at a higher level to represent a combination of said
set of objects at said first level such that the configuration of said
higher level object as displayed is indicative of the total resources
required to perform the tasks represented by the objects at the first
level.
4. The method of claim 3 wherein said generating step includes,
automatically changing the configuration of said higher level object in
response to changes made to an object in said set at said first level.
5. The method of claim 3 wherein said indicating step includes
indicating the times at which said first level tasks are to begin and end
by the position of said higher level object on said display.
6. A method to aid graphically the management of a set of tasks, comprising
the steps of
representing a quantity associated with each task by a geometric object of
at least two dimensions whose geometric area or volume is indicative of
said quantity,
displaying each said geometric object on a display device,
graphically indicating information about dependencies in the performance of
said tasks on said display, and
arranging objects on said display to graphically indicate the spatial
independence of sets of tasks.
7. The method of claim 6 wherein
said sets of tasks are repetitive tasks to be performed at different
locations, and
said arranging step includes
representing said sets of tasks by objects arranged along parallel rows on
said display.
8. The method of claim 7 wherein said arranging step includes
organizing said repetitive tasks in groups to be performed by respective
work crews, where a given work crew works on all tasks within a group
regardless of location, and
arranging said objects on said display to indicate the sequence of tasks to
be performed by each said work crew.
9. The method of claim 8 wherein said arranging step includes
positioning the tasks in each said row to reflect the dependencies of said
tasks.
10. A method to aid graphically the management of a set of tasks,
comprising the steps of
representing a quantity associated with each task by a geometric object of
at least two dimensions whose geometric area or volume is indicative of
said quantity,
displaying each said geometric object on a display device,
graphically indicating information about dependencies in the performance of
said tasks on said display, and
providing a user interface to permit the user to alter the size, shape, and
location of each said object on said display.
11. The method of claim 1, 2, 3, 6 or 10 wherein said representing step
includes indicating the period of time required for said task by the
extent of said object along one said dimension.
12. The method of claim 1, 2, 3, 6 or 10 wherein said representing step
includes indicating an amount of resources per unit time required for said
task by the extent of said object along one said dimension.
13. The method of claim 1, 2, 3, 6 or 10 in which said quantity associated
with each said task comprises the aggregate amount of resources required
for said task.
14. The method of claim 13 in which said resources comprise money, or
manpower, or quantity of work.
15. The method of claim 1, 2, 3, 6 or 10 wherein said indicating step
includes
indicating information about dependencies in the performance of said tasks
by the position of each said object in the display.
16. The method of claim 1, 2, 3, 6 or 10 wherein said dependencies in the
performance of said tasks include temporal dependencies.
17. The method of claim 1, 2, 3, 6 or 10 wherein said indicating step
includes
indicating dependencies in the performance of said tasks by lines
connecting the objects.
18. The method of claim 1, 2, 3, 6 or 10 in which said object occupies a
position on said display that is indicative of the times when said task is
to begin and end.
19. The method of claim 18 in which the display defines a time axis and
said objects are arranged along said time axis to indicate the relative
times when said tasks are to begin and end.
20. The method of claim 1, 2, 3, 6 or 10 in which said object is a
quantified bar.
21. The method of claim 1, 2, 3, 6 or 10 in which said object is associated
with a task in a construction project.
22. The method of claim 1, 2, 3, 6 or 10 wherein said indicating step
includes
graphically indicating on the display device information about the required
sequence in which tasks are to be performed.
23. The method of claim 22 wherein said indicating step includes
graphically indicating the required sequence by joining the boundaries of
successive objects in the sequence.
24. The method of claim 22 wherein said indicating step includes
graphically indicating the required sequence by lines connecting said
objects.
25. The method of claim 1, 2, 3, 6 or 10 further comprising the step of
displaying alphanumeric data corresponding to said objects in a table
associated with said display of said objects.
26. The method of claim 25 in which said alphanumeric data includes
information about the times when each said task is to begin and end and
the resources per unit time required for said task.
27. The method of claim 26 further comprising the step of
computationally linking said table and said objects so that changes made to
either said objects or said table are automatically translated to changes
in the other.
28. The method of claim 25 wherein said displaying step includes
simultaneously displaying said table and said objects.
29. The method of claim 25 in which said table is in the form of a spread
sheet in which cells are related by computational rules.
30. A method to aid graphically the management of a construction project
which includes a set of tasks, comprising the steps of
representing each task by a quantified bar whose area is indicative of a
quantity of resources required for said task,
displaying each said quantified bar on a display device, and
graphically indicating information about dependencies in the performance of
said tasks on said display either by the positions of said objects or
lines interconnecting the objects.
31. A method to aid graphically the management of a set of tasks,
comprising the steps of
representing a quantity associated with each task by a geometric object of
two dimensions and more than four sides and whose geometric area or volume
is indicative of said quantity,
displaying each said geometric object on a display device, and
graphically indicating information about dependencies in the performance of
said tasks on said display.
32. Apparatus to aid graphically the management of a set of tasks,
comprising
object generator means for generating for each task a geometric object of
at least two dimensions whose geometric area or volume is indicative of a
quantity associated with said task,
a display device for displaying each said geometric object, and
dependency generator means for indicating graphically on said display
information about dependencies in the performance of said tasks.
33. Apparatus to aid graphically the management of a set of tasks,
comprising
object generator means for generating for each task a geometric object of
at least two dimensions whose geometric area or volume is indicative of a
quantity associated with said task,
a display device for displaying each said geometric object, and
dependency generator means for indicating graphically on said display
information about dependencies in the performance of said tasks including
indicating spatial independence between said tasks performed at spatially
distinct locations.
34. Apparatus to aid graphically the management of a set of tasks,
comprising
object generator means for generating for each task a geometric object of
at least two dimensions whose geometric area or volume is indicative of a
quantity associated with said task,
a display device for displaying each said geometric object,
dependency generator means for indicating graphically on said display
information about dependencies in the performance of said tasks,
association means for associating a set of said objects representing
related tasks at a first level of said project together on said display
device, and
hierarchy means for generating an object at a higher level to represent a
combination of said set of objects at said first level such that the
configuration of said higher level object as displayed is indicative of
the total resources required to perform the tasks represented by the
objects at the first level.
35. Apparatus to aid graphically the management of a set of tasks,
comprising
object generator means for generating for each task a geometric object of
at least two dimensions whose geometric area or volume is indicative of a
quantity associated with said task,
a display device for displaying each said geometric object, and
dependency generator means for indicating graphically on said display
information about dependencies in the performance of said tasks, and for
arranging objects on said display to graphically indicate the spatial
independence of sets of tasks.
36. Apparatus to aid graphically the management of a set of tasks,
comprising
object generator means for generating for each task a geometric object of
at least two dimensions whose geometric area or volume is indicative of a
quantity associated with said task,
a display device for displaying each said geometric object,
dependency generator means for indicating graphically on said display
information about dependencies in the performance of said tasks, and
a user interface to permit the user to alter the size, shape, and location
of each said object on said display. |
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Claims |
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Description |
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BACKGROUND OF THE INVENTION
This invention relates to task management.
Projects and group activities often involve tasks whose sequence must be
planned and monitored in light of the resources required and available.
In the construction of concrete buildings, for example, such tasks as
concrete work, form work, carpentry, and finish work, must be coordinated,
and the available resources, such as working crews and equipment, must be
distributed among them systematically. The construction planner, based on
experience, must plan the sequence in which the work will be done, and the
rate at which resources will be devoted to any task (e.g. how many men to
include in the work crew that will pour the concrete foundation).
During construction, the effects on the plan of changed circumstances, such
as design alterations, labor strikes, or unforeseen underground
obstructions, must be considered by the construction superviser.
One method of construction scheduling is the critical path method, CPM, in
which diagrams depict the stages of a project as nodes, and the durations
of the tasks required to reach the successive stages as arrows. In a
variation of CPM, known as PERT, ranges of task duration may also be
shown. Additional information, such as cost or number of workers, may be
added in the form of text along the arrows or on the nodes of the diagram.
Another technique, linear scheduling, depicts repetitive tasks by a line
plotted on a coordinate system in which the horizontal axis represents
time, the vertical axis represents location, and the slope of the line
represents the projected production rate for the task.
SUMMARY OF THE INVENTION
In a general feature of the invention, the management of a set of tasks is
aided graphically by a technique in which a quantity associated with each
task is represented by a geometric object of at least two dimensions whose
geometric area or volume is indicative of the quantity; each geometric
object is displayed on a display device; and information about
dependencies in the performance of the tasks are indicated graphically on
the display.
Preferred embodiments of the invention include the following features.
Each object is a rectangular quantified bar. The extent of an object along
one dimension is indicative of the period of time required for the task,
and the extent of the object along one dimension corresponds to an amount
of resources per unit time required for the task. The quantity associated
with each task is the aggregate amount of resource (e.g., money, or
manpower, or quantity of work) required for the task.
The information about dependencies of the performance of the tasks
(including temporal dependencies or spatial independence) is indicated by
the position of each object on the display (e.g., by shared boundaries
between objects) or by lines connecting the objects. The display defines a
time axis and the objects are arranged along the time axis to indicate the
relative times when the tasks are to begin and end.
A set of objects representing related tasks at a first level of the project
are associated together for display, and an object is generated at a
higher level to represent a combination of the set of objects at the first
level such that the configuration of the higher level object as displayed
is indicative of the total resources required to perform the tasks
represented by the objects at the first level. When changes are made to an
object at the first level, the configuration of the higher level object is
changed automatically.
Alphanumeric data corresponding to the objects are displayed in a table
associated with the display of the objects. The alphanumeric data include
information about the times when each task is to begin and end and the
resources per unit time required for the task. The table and the objects
are computationally linked so that changes made to either the objects or
the table are automatically translated into changes in the other. The
table and the objects are displayed simultaneously. The table is in the
form of a spread sheet in which cells are related by computational rules.
The sets of tasks are repetitive tasks to be performed at different
locations and are represented by objects arranged along parallel rows on
the display. The objects are arranged on the display to indicate the
sequence of repetitive tasks to be performed by a work crew. The tasks in
each row are positioned to reflect the dependencies of the tasks.
A user interface permits the user to alter the size, shape, and location of
each object on the display. In some embodiments, the tasks are tasks in a
construction project.
The system is interactive, readily understandable, capable of generating
meaningful visual images which are useful for the development of schedules
and easily updated. It can be employed to develop an initial schedule,
monitor progress, generate forecasting information, and manage a project
or group activity. Large amounts of information can be effectively
displayed in a small space. The hierarchical structure allows rapid
switching between high level charts and those which depict the greatest
level of detail. Labor is made easier. The system enables the project
planner to make the best use of his experience and judgment.
DESCRIPTION OF THE PREFERRED EMBODIMENT
We first briefly describe the drawings.
FIG. 1 is a diagram of a quantified bar.
FIG. 2 is a diagram of the relationships among resources for a construction
project.
FIG. 3 is a diagram of possible relationships among quantified bars.
FIG. 4 is a diagram of a template including a quantified bar chart.
FIG. 5 is a diagram of a matrix balanced chart for finish work on the
various different floors of a building.
FIG. 6 is a diagram of a spread sheet corresponding to FIG. 4.
FIG. 7 is a diagram like FIG. 4 at an earlier stage of development.
FIG. 8 is a detailed template at a level below the template of FIG. 4.
FIG. 9 is a spread sheet for all floors of a building.
FIGS. 10, 11 are diagrams illustrating contraction and expansion of tasks.
FIGS. 12 through 18 are successive stages in the development of the matrix
balanced chart of FIG. 5.
FIG. 19 is a diagram illustrating critical path considerations
corresponding to the diagrams of FIGS. 12 through 18.
FIGS. 20, 21, and 22 are diagrams of alternative techniques for
illustrating the relationships of the tasks shown in FIG. 5.
FIGS. 23, 24 are diagrams illustrating the monitoring of the projects which
are depicted in FIGS. 4 and 5, respectively.
FIG. 25 is a block diagram of a system for graphically aiding the
management of a set of tasks.
FIG. 26 is a chart of templates and matrix balanced schedules for a
construction project.
FIGS. 27 and 28 are flow charts illustrating, respectively, the generation
of quantified bar charts and matrix balanced quantified bar charts.
FIG. 29 is a flow chart illustrating the planning of a project.
STRUCTURE AND OPERATION
In the invention, a project planner or a project superviser can
interactively develop and display on a computer terminal graphical
representations of the tasks that make up the project and the temporal and
spatial relationships of the tasks. By manipulating the graphical
representations or related data, the planner or superviser can, among
other things, adjust the plan, consider hypothetical situations, and
monitor the performance of the project at successive stages.
Referring to FIG. 1, in building a graphical representation of a project,
each one of a set of tasks to be managed is depicted by a quantified bar
10 in the form of a rectangular geometric object positioned within a two
dimensional coordinate plane 12. The horizontal axis 14 represents time,
and the vertical axis 16 represents resources per unit time, for example,
manpower per unit time, cost per unit time, or quantity of work per unit
time. The length 18 of the quantified bar 10 corresponds to the duration
of the task and the height (also called the width) 20 of the bar to the
resources dedicated to the task per unit time. The position of the bar 10
along the horizontal axis 14 depicts the timing of the task. The positions
of the left and right sides of the bar along the horizontal axis
correspond to the starting and finishing times 22, 24 of the task.
Thus, the area of the quantified bar represents the total quantity of
resources (man-days, cost, or quantity of work) required for the task.
Referring to FIG. 2, the total manpower 30 (e.g. man-days) multiplied by
the wage rate 32 (e.g. dollars per man-day) gives the total cost 34; total
cost 34 (e.g. dollars) is also quantity of work 36 (e.g., cubic yards of
concrete) multiplied by unit cost 38 (e.g., dollars per cubic yard).
Quantity of work 36 divided by productivity 40 (e.g. cubic yards of
concrete poured per man-day) gives manpower 30. Manpower, cost, and
quantity of work all influence, and are affected by, the construction
method 42. Wage rate affects both productivity and unit cost, and
productivity also affects unit cost.
In construction work, for example, these conversion factors will depend on
such things as the construction technology, the expertise of the
construction workers, and the characteristics of the project. Thus in a
quantified bar of a given length (duration) and width, the width can
equally well be made to represent manpower or quantity of work or cost, in
each case per unit time, simply by noting that
duration=quantity of work/number of men.multidot.productivity
duration=total cost/cost per day
duration=manpower/number of men
The system can easily change the resources represented by the quantified
bar provided it knows the appropriate conversion factors represented by
unit cost, wage rate, and productivity, and these may be entered by the
user.
For purposes of scheduling, discrete tasks are depicted on the terminal
display device as separate quantified bars. A discrete task is either
independent or dependent with respect to any other discrete task.
Referring to FIG. 3, dependent relationships are depicted by joining the
quantified bars either by arrows or by common points or boundaries. Two
tasks 50, 52 which are independent may each start and end without
reference to the other task. For dependent tasks, three possible
interrelationships may be set up. If one of the tasks 54 cannot start
until the other task 56 is finished, the tasks are considered continuous.
If one task 58 can start after the other task 60 is started but before
that other task is completed, the tasks are considered overlapping.
Finally, two tasks 62, 64 which may need to be carried out at the same
time are considered parallel.
A critical path for the scheduling of discrete tasks thus may be depicted
by the relative positions of and links between the quantified bars that
represent the tasks. Where the critical path permits some float between
two successive tasks, the float will allow the quantified bars
representing the two tasks to be separated by a variable amount of time.
The system provides for the creation of interrelated quantified bar charts
at varying levels of detail in a hierarchical structure. For example, at a
macro level, a single quantified bar may represent all concrete work for a
project. At a lower level there may be corresponding quantified bars for
each of the different concrete tasks, e.g., foundation, columns, and
floors. At any particular level of detail, a quantified bar thus may
represent a discrete task or a group of discrete tasks.
Although we have thus far described the representation of tasks only in
terms of the quantified bars, the numerical and alphabetic information
that corresponds to the bars and their relationships is also stored in the
computer in a spreadsheet form, and links between the data and the
quantified bars allow the computer to maintain continuing consistency
between the two.
The quantified bars (together with the corresponding numerical and textual
data at a given level) make up a template. Referring to FIG. 4, for
example, a template for the structural skeleton of a typical floor of a
building might consist of data and quantified bars for tasks related by
job code.
In FIG. 4, dependencies among quantified bars are depicted by the relative
starting and ending times of the bars. On the left side of FIG. 4
(generally to the left of line 68) are the quantified bars; on the right
side are the related data in spreadsheet form. Four tasks are defined:
concrete, mechanical and electrical (M&E), re-bar, and form. Concrete work
begins on the tenth day, continues into the eleventh day (the length of
bar 72 is greater than one day), and uses 14 men per day for an aggregate
manpower of 20 man-days. The table of data indicates that the quantity of
work would by 8000 ft.sup.3, and the productivity would be 400 ft.sup.3
per man-day, requiring 20 man-days. Thus note that bar 72 could
alternatively represent the 8000 ft.sup.3 total concrete by a width
corresponding to 8000 ft.sup.3 (14 men/20 man-days)=5600 ft.sup.3 /day.
The mechanical and electrical work, represented by quantified bar 74, must
end on the ninth day (before the concrete work begins). Bar 74 has a
duration of one day, uses 8 men, and has a width of 8 men per day. Note
that, although only 100 man-days are required, it is assumed that the 8
man crew will be on the job 6 full days so that 108 man-days could
actually be performed.
The information on the template represents a combination of experience of
the planner (for example the knowledge that re-bar work must precede
mechanical and electrical work) and the requirements of the tasks that
make up the project (for example the fact that 8000 cubic feet of concrete
are required).
The system is capable of aggregating a group of related tasks of a template
at one level to form a composite quantified bar for use in a higher level
template. This procedure is referred to as "folding-up." The higher level
quantified bar representing the aggregated tasks has a length determined
by the critical path for the group of tasks. The length corresponds to the
duration of the aggregated tasks when performed in the sequence and with
the time constraints required by the critical path. The area of the
folded-up quantified bar corresponds to the total resources required by
the aggregated tasks.
Each template, in addition to the numerical and textual data and the
quantified bars associated with related tasks may also contain a display
of the folded-up bar resulting from aggregating all of the tasks depicted
in the template. In FIG. 4, for example, quantified bar 76 (below double
line 70) is a folded-up version of all of the quantified bars above double
line 70. Bar 76 is 10+ days long and has a width of 16+ men for an
aggregate of 176 man-days. On the data side (opposite bar 76) are shown
the average labor cost of $202 per man-day and the corresponding total
labor cost of $35,600. Bar 76 and the associated data could appear as one
entry in a higher level template.
The example above concerned a set of tasks that were related by a critical
time path, an arrangement that is particularly useful for projects like
the structural work for a high-rise building. The invention is also useful
for scheduling repetitive activities, for example, the finish work on the
different floors of the building, where floors can be worked on
simultaneously or in any order.
Referring to FIG. 5, for example, information can be stored and displayed
as quantified bars that represent tasks to be performed at each one of a
number of successive locations.
In FIG. 5, quantified bars are arranged in groups as indicated by their
respective shadings. The solid bars 80, for example, could each represent
mechanical and electrical work on a given floor. Successive floors (3
through 13) are represented by successive layers arranged in the vertical
direction, with each layer referring to a different floor in the building.
The relative starting times and dependencies of discrete tasks are
displayed simultaneously for all floors, facilitating refinements to the
scheduling.
In layer 84, for instance, the relative locations of the quantified bars in
the horizontal direction on a given floor indicate the relative scheduled
starting times of the different tasks on that floor, with the relative
starting times satisfying the critical path as to a given floor. The
horizontal spacing between some tasks indicates the float permitted by the
critical path.
At the same time, dependencies between like tasks to be performed on
successive floors may be worked out and displayed. For example, bars 80,
82, 86, 88, may represent part of the mechanical and electrical task to be
performed by a given work crew on successive floors. After completing the
task on floor 3, the crew proceeds to perform the same task on floor 4,
and so on. Another work crew may begin on a different aspect of the
mechanical and electrical task on floor 3 (bar 90), then proceed to floor
4 and so on. Although that crew will begin its work on floor 3
substantially later than the first crew, it will work faster per floor
and, by floor 7 would find itself interfering with the first crew. To
avoid the inefficiencies of those two crews working together on the same
floor, the second crew would go next to floor 9 (as indicated by
connecting line 92), then to floor 7 (line 94), then to floor 8, and so
on.
Note that the tasks depicted in FIG. 5 form a matrix of quantified bars
arrayed over time (along the horizontal axis) and location (along the
vertical axis). Reaching a schedule through the alterations of relative
starting times and sequence for the tasks and their dependencies based on
all of the template information organized by location is described as a
"matrix-balanced scheduling method." Note also that in FIG. 5, the
improving productivity of a work crew as it proceeds from floor to floor
and becomes more efficient in its work may be represented by a changing
slope of a line passing through the centers of the bars on successive
floors.
We turn now to a more detailed explanation of how the quantified bar chart
of FIG. 4 would be generated.
Referring to FIGS. 6 and 27, the planner first stores (160) in the cells of
a spreadsheet the data for the template. Each line in the spreadsheet
represents a crew specialty (column AE) and each column represents some
aspect of the work of that crew. The planner would enter the quantity of
work (columns AF and AG), the contracted unit cost (columns AH and AI),
the total contracted cost (column AJ), and the wage rate (column AK). The
computer would then augment the spreadsheet data (162) by calculating the
manpower required (column AL) based on the contracted cost and the wage
rate, and the productivity (column AM) based on the quantity of work and
the calculated manpower. The computer could also report the experienced
productivity rate (column AN) based on other projects. The planner would
then, based on experience, adopt a productivity value (column AO). The
computer would then calculate the adopted manpower value (column AP) based
on the quantity of work and adopted productivity. The planner might then
specify that the job is to be done in about 10 days, and the computer
would calculate the actual working days required and the size of the crew
(columns AQ and AR).
The computer would also automatically generate the totals shown in row 15.
As indicated by the line 164, the computer thus aids the planner to
complete the spreadsheet (168) by an iterative process.
Referring also to FIG. 7, as the data is being entered on the spreadsheet
by the planner, the corresponding quantified bars are being automatically
generated (162), reflecting the data in columns AQ and AR of FIG. 6. The
planner specifies the vertical and horizontal scales for the bars and
indicates whether the vertical scale is to represent quantity, manpower,
or cost (160).
Note that the dependencies among the bars in FIG. 7 have not yet been shown
because they have not yet been indicated by the planner. The planner's
next step is to indicate those dependencies, either by moving the bars
using a mouse, or specifying numerically the starting and ending times for
each block. The result is the quantified bar chart of FIG. 4.
The planner could alternatively have created the quantified bars directly
(170) using the mouse, and the computer would have generated (172) the
corresponding data in columns AQ and AR and other columns that are
affected.
The computer also automatically performs the folding up operation to create
bar 26 of FIG. 4, and the corresponding aggregate values in row 15 at
columns AP, AQ, AR. Furthermore, the folded up bar and aggregate values
may be used in a higher level template and any changes in them will
automatically be reflected in that higher level template.
By developing lower level templates in detail, it is possible to impart
more precision to the higher level template. Referring also to FIG. 8, for
example, the form and re-bar tasks of the template of FIG. 4 are broken
down into more detailed level tasks with the critical path relationships
represented by the positions of the bars.
Having developed the quantified bar chart for one floor of the building,
the planner may then easily expand his analysis (174) to the other floors.
Referring also to FIG. 9, for example, the concrete work, form work, re
bar work, and M & E work can be arrayed across a spreadsheet with each
line representing one floor of a building. The information from FIG. 6 may
be entered on, say floor 7, line 12 of the new spreadsheet. Assuming that
floor 7 is fairly typical, the same data can be spread to the other floors
on the basis of a ratio of floor area (columns B and C). Thus by entering
the floor areas or even the ratio values, the planner can cause the other
floors to inherit the values from floor 7 or appropriate fractions of
those values. Similar ratios are provided in columns H, M, R, and V. Once
the full spread sheet has been developed by the computer based on the
inheritance principle, the planner may use his judgment to alter specific
values on specific floors (176). Roof work, for example, is different from
the work on the other floors and the two cannot be related by a simple
ratio based on floor area. The quantified bars for form work are shown in
black and for re-bar work are shown shaded. The folded up bars at the
bottom of FIG. 8 correspond to the re-bar and form work bars of FIG. 4.
As with any quantified schedule, FIG. 9 is automatically converted by the
computer to a quantified bar chart (178). Referring to FIG. 10, each bar
in the chart represents the work required for one of the floors (column AB
of FIG. 9) and the bars are arranged to reflect the assumption that a
single crew will begin at the basement and finish each floor in
succession. The planner may then determine whether the total time
contemplated is too great, or shorter than need be.
If too short, the planner can extend (180) the time by reducing the number
of men on the crew, either floor by floor or for all floors (the upper
half of FIG. 11 shows an extension based on increasing the crew size for
all floors). If the total time is too great, it may be reduced by
increasing the crew size, as seen in the bottom half of FIG. 11. The
change can be made either by using a mouse to manipulate the quantified
bars themselves or by changing the data on the quantified schedule. Note
that an increase in crew size produces wider, but shorter bars and a
decrease in crew size produces narrower, but longer bars, as expected.
In general, quantified bars may be modified in a variety of ways, including
a shift along the time axis within the float constraints (182) applicable
to the bar, expansion or contraction along the time axis or the total work
axis (as in FIG. 11), aggregation of two related serial activities into a
single quantified bar, and aggregation of two parallel activities into a
single bar spanning the same time period.
Referring to FIG. 29, thus the system may be used iteratively to develop a
plan for the performance of the various tasks of a project. First the
planner estimates the quantities of resources for the tasks (210),
establishes the method of completing the project based on selected tasks
(212), decides the sequence of specific tasks (214), and decides the
duration of specific tasks (216). Then with the aid of software (218),
including speed conversion factors (220, 222), the corresponding
quantified bar charts can be displayed (224) to the planner. If the plan
represented by the charts is acceptable (226) it is implement (228);
otherwise adjustments are made iteratively (230).
Referring to FIG. 28, we now turn to a description of how the matrix
balanced quantified bar chart of FIG. 5 for the finish work on a building
might have been generated by a planner.
Referring also to FIG. 12, first the planner develops a detailed template
(190) for the ceiling, floor, and wall tasks (separated vertically in the
figure) for a representative room on a typical floor organized by crew
specialty (depicted by bars of different shading). Critical path
considerations are then added (192), as in FIG. 13.
Referring also to FIG. 14, next the bars are compressed vertically (194) to
eliminate any distinction among tasks and to make it easier to integrate
the template to a higher level.
Referring also to FIG. 15, the template is converted to one for the whole
floor (196) by taking account of variations in rooms across the floor, and
the floor template is further adjusted to move the bars (198) into two
streams (upper and lower) designed to reflect the use of two crews working
in parallel. The tasks performed in the two streams are reallocated (201)
to reduce the total time while still satisfying the critical path
requirements (FIG. 16). After further simplification (FIG. 17), the
template is ready for inclusion as one floor in a matrix balanced chart of
the whole building.
Referring to FIG. 18, the finish work for floors 3 through 12 has been laid
out (203) without consideration for labor leveling. That is, it may be
inefficient to perform the work in the manner suggested by FIG. 18,
because doing so may require more men in the middle of the job than at the
beginning and end.
Referring to FIG. 19, by reconsidering the float associated with the
critical path of the finishing process, it is possible for the planner to
improve the labor balance (205) for the job as a whole. In FIG. 19, the
floats are indicated by horizontal arrows.
Referring to FIG. 20, if one were to array the bars for the various
activities by joining them corner to corner (to represent for example that
when the floor cleaning crew is done cleaning floor 3, it proceeds to
clean floor 4), then the bar chart will not easily depict the work on a
floor by floor basis because of the varying widths of different tasks.
Referring to FIG. 21, on the other hand, if the tasks were all forced to
have the same width (which would then depict the floors in a visually
sensible manner) the information about the resources required for each
task is lost.
Referring again to FIG. 5, by using the matrix balanced chart of the
invention, both the resources required by each task and the floor by floor
arrangement of tasks are visible on the chart.
Referring also to FIG. 22, the matrix balanced bar chart can be reduced to
a quantified bar chart in which the bars are organized by activity rather
than by floor. In FIG. 22, the process of conversion has not been
completed. Dashed line blocks are blocks of FIG. 5 that have been
reorganized by activity.
This facilitates the planner's work in adjusting the tasks to achieve labor
balance as reflected on the finished chart of FIG. 5.
The quantified bar chart may also be converted to a conventional bar chart,
by making all the bars of equal width (i.e., eliminating any variation
based on resources required).
Referring to FIG. 26 the overall plan for a construction project could
include a master matrix balanced chart 150, supported by matrix balanced
charts for temporary work, structure work, finishing work, and external
work 152, 154, 156, 158, with corresponding templates and microtemplates
at lower levels.
The project planner or project superviser may also use the created
templates for monitoring the progress of the project. Referring to FIG.
23, for example, the actual experience with respect to the template of
FIG. 4 has been superimposed on the original template. The user enters
actual data on a daily basis on the lowest level templates.
Referring to FIG. 24, another kind of monitoring can be easily done from a
monitoring chart generated by the computer directly from the matrix
balanced schedule. Shaded blocks indicate tasks that have been completed
on various floors.
The system would be implemented on an appropriately programmed workstation
using software that would permit interactive development of templates and
monitoring of project progress.
The system would be menu-driven, and would ideally use icons and other
graphical tools to enhance the interface. Cursor control could be through
a mouse.
Inheritance techniques would be used to reduce the effort in generating
duplicative templates, such as for multiple floors and multiple rooms, as
previously explained.
The software would permit the user complete freedom to view any template at
any level, to adjust any template at any level, and to monitor the project
at any level.
The software would, at all levels, provide as much assistance as possible
to the user in terms of computing values and displaying bars. For example,
as previously mentioned, when the user manipulates a quantified bar with a
mouse, for instance, the system automatically converts this information
into a new entry in the appropriate section of the spreadsheet in the
template after the user indicates that the manipulation of the quantified
bar is completed. If the user changes the horizontal dimension of a
quantified bar to denote a change in the duration of a task, the system
adjusts the dedicated resources by changing the vertical dimension of the
quantified bar, denoting a change in the dedicated resources. When changes
are made to either the vertical dimension or the horizontal dimension of a
quantified bar by the user, and the total work involved in the task is not
altered, the system automatically maintains the same area for the
quantified bar and makes the appropriate adjustments. If the user directly
alters the alphanumerical data in the spreadsheet in the template, the
system automatically changes the visual configuration of the quantified
bars in a corresponding fashion. In addition, after changes are introduced
to one or more quantified bars in a template, the system automatically
adjusts the folded up bar in the template.
A user may alter data in any level of the hierarchy. When changes are
introduced at one level of the hierarchy, the corresponding folded up bar
is automatically altered and this information is automatically transferred
to all higher levels in the hierarchical system. However, the system
cannot automatically transfer changes to lower levels of the hierarchy
unless the user defines specific relationships to be followed. For
instance, a change in the duration of a task at an intermediate level can
be automatically transferred to higher levels in the hierarchical
structure since the higher levels encompass a lower level of detail.
However, in the absence of prestored relationships, the system cannot
translate a change in the duration of the task into a lower level of the
hierarchy in which the altered task is broken down into two or more sub
tasks. Therefore, the system contains two types of functions to handle the
related modification of lower level templates. The user may define
standard relationships. An example of such a relationship would be setting
a function so that any modification of the duration of a task would be
equally spread among all subtasks into which the task is broken down at
lower levels. An alternative relationship might be spreading a change in
duration of a task proportionately among the subtasks into which the task
is broken down at lower levels, based upon the existing relative durations
of the subtasks.
In the absence of preset relationships allowing the system to automatically
adjust lower levels, the system would automatically display a warning on
the template displays of the unadjusted lower levels indicating that they
are out of date. The user may alter the lower levels either directly,
based upon specific data for the particular level, and remove the warning
indication, or the user may set relationships allowing the system to make
change to the lower levels, automatically indicating, as above, that the
changes are estimates.
Changes in the starting times of various tasks are among the types of
modifications which the user may frequently wish to introduce. One task
may not be started until another task is completed. Therefore, if the user
attempts to change the starting time of an activity in such a way that it
would violate a preset dependent relationship, the system will not accept
the change. The user may then either readjust all dependent tasks in such
a way as to not violate the preset dependencies or, if possible, the user
may reset the dependencies.
For instance, a user change in the data for the resources dedicated to a
discrete task at an intermediate level of detail (but without any change
to the critical path) results in an alteration of the shape of the
quantified bar at that level of detail. A new folded up bar for the tasks
in the template to which the change was made is automatically generated.
This change in the folded up bar in the template automatically results in
a change in the corresponding quantified bar in a template at a higher
level, which in turn is automatically carried up through all higher levels
of the system. Changes | | |
