WO2009122175A2 - Method and apparatus for analytical problem solving - Google Patents

Description

METHOD AND APPARATUS FOR ANALYTICAL PROBLEM SOLVING

The present invention relates to computer-based tools for automatically assisting in complex problem solving, in particular though not exclusively in which the problem solving represents design or design planning processes. The problem solving, or design / design planning processes, may relate to a wide variety of industrial sectors, such as the design of a building, an automobile or other complex structure.

There are a number of methods and associated computer-based tools available which assist a user to design and plan a number of independent and interdependent tasks or operations necessary to complete a complex undertaking, such as the design of a building. These methods and computer-based tools generally assist or facilitate the scheduling of all the design and construction activities required in order to complete the complex undertaking.

An analytical design planning process comprises the steps as indicated in figure 1. With reference to figure 1 , the first step is to generate a model 10 of the design process, which defines the activities and their information requirements.

From this model, a table 12 of activities is generated, listing the information requirements and dependencies of the individual activities, together with an indication of the classification of any such information dependencies. Next, a dependency structure matrix (DSM) analysis tool is linked to the model or table via a database or other file structure and identifies the optimal sequence of activities and iterations within the design process and displays them in a dependency structure matrix 14. Finally a programme or schedule of activities 16 often referred to as a Gantt chart is generated from the DSM 14.

The information dependency table 12 basically comprises a list of tasks or activities in the process model and indicates the various information inputs required for the completion of that task. Study of an information dependency table 12 and design process data flow diagram shows that many complex loops and interrelated dependencies will become apparent in any complex undertaking, such as the design of a building. Manually resolving these various interdependencies becomes a near impossible task in the design of complex undertakings. UK patent 2381627B describes a system for providing automated assistance to a user to greatly improve the dependency structure matrix analysis process and automatically generate a dependency structure matrix (DSM) 14 to assist in the refinement of the design to a workable solution.

A simple example of a dependency structure matrix 14 is demonstrated in figure 2(a). As can be seen, the design tasks are listed arbitrarily in the rows of the matrix (for ease of understanding in this example they happen to be ordered numerically) and that order is mirrored in the columns. The DSM works on the assumption that the activities are undertaken in the order suggested by the rows (and columns, which are always in the same order as the rows). The dependence of one activity (e.g. task 2) on another (e.g. task 7) is indicated by placing a mark in row 2, column 7 of the matrix. In this case, the mark is a category "C", indicating a relative importance of task 7 to task 2, useful when selecting task interrelated dependencies to break. The excluded "self-dependency" positions of the matrix are shaded out as the black diagonal line 31.

Thus, a "mark" or filled box 33, 34, 35 in the matrix 14 indicates that the activity or task on the left hand side of the matrix is dependent upon the activity at the top of the matrix. It will be understood that a mark placed below the diagonal line 31 indicates that an activity is dependent upon the information that has been produced by a previous activity, while a mark placed above the diagonal line 31 indicates that an activity is dependent upon information that has yet to be produced, i.e. dependence on a future activity. As a consequence, there will have to be some iterative process in the design to either resolve this future dependency, or provision of estimated information to replace that which is not yet available.

In the real world, of course, estimation of information or other dependencies for feeding forward leads to inefficiency. For example, it may be necessary to estimate the load bearing requirements of a particular structure in a building, or a quantity of materials required, and this must be done by suitable overestimate to ensure safety. Estimates made can be revised later once subsequent design tasks have been carried out, but this is inefficient in the design process since it requires revisiting certain tasks and results in iterative loops in the design process.

UK patent 2381627B describes a system for minimising the number of iterations required and the size of the iteration loop. The matrix is analysed and the tasks are resequenced in such a manner as to minimise the number of future dependencies. However, even where this has occurred, there are generally still a number of looped dependencies which have to be managed when transferring the information content of the DSM to a project management activity schedule or Gantt chart 16.

The Gantt chart is an effective means for representing processes in relation to time and is readily visualised by the user. Automated tools for displaying and manipulating Gantt charts are widespread and are a preferred way of manipulating process flows during execution of a process, e.g. in response to real time events and circumstances that dictate a readjustment in a process flow. This is because many users find it much easier to visualise a complex process as a time sequenced set of events or activities. However, a Gantt chart does not take account of interdependency between scheduled activities.

That interdependency information is readily contained within the DSM 14.

Therefore, existing automated tools and techniques for planning and representing processes in relation to time (e.g. Gantt charts) do not take account of interdependency between activities. In this respect, in order for any events that are interdependent (i.e. dependent upon one another) to be sequenced in time, the logic flowing backwards (i.e. against time) between activities is removed thus enabling accurate calculations to be undertaken to determine the path through the process. This is problematic when planning, managing and controlling interdependent processes such as design - where information to enable decision-making flows back and forth between activities during extended periods. In removing the 'backward flowing' logic, the true impact of any changes to the sequence of events resulting from constraints and/or opportunities arising during the delivery of the process cannot be truly understood. Put simply, if the actual logic in the process is not retained, even when not being considered or used when reviewing a time-based series of events, any analysis undertaken neglects to take account of the true interdependence of the process and as such, is likely to be flawed.

Furthermore, during project management, it is a common requirement to be able to make adjustments to the scheduling of activities in the Gantt chart representation 16. Such adjustments may include alterations in the duration and relative positioning of scheduled tasks in the program sequence. However, without logic representing the full interdependency of tasks being embedded in the data representing the Gantt chart, any adjustments in the duration and relative positioning of tasks in the Gantt chart will ignore the impact of breaking dependencies and any effects of looped dependencies. Methodologies and computer programs exist that enable the optimum sequence or path through a series of time-based events to be determined. However, none of these methods and computer programs enable backward flowing logic to be retained during the time sequencing process.

Thus, there is difficulty in understanding the full impact of imposing changes to a time- based Gantt chart which by itself represents only the forward part of the dependency logic in the process, particularly where changes impact upon elements of interdependence which are not represented.

Keeping track of the knock-on effects that may result from changes in the process is difficult and means further rescheduling of activities. Considerable effort is required to continually manually update the Gantt chart in a bid to reflect the impact of forced changes due to task interdependencies.

It is an object of the present invention to mitigate or overcome current difficulties associated with the above problems.

It is a further object of the invention to enable the retention of process interdependency during time-based sequencing of events (e.g. in an automated Gantt chart representation) so that the impact on interdependency of changes to the time-based sequence can be analysed.

It is a further object of the invention to provide an automated process for displaying and enabling manipulation of a time-based sequence of activities in a Gantt chart and providing an interface to DSM manipulation apparatus (such as that described in GB 2381627B referenced above) such that activity information manipulated by the user in the Gantt chart domain can be automatically fed back to the DSM domain for further display and manipulation without loss of critical interdependent process flow information.

Some or all of the above objects may be achieved in the present invention.

According to one aspect, the present invention provides an apparatus for assisting in the manipulation of a time-sequenced series of interdependent and dependent activities comprising: a database for receiving a DSM data set representing a dependency structure matrix having a plurality of elements each having data dependency on other ones of the plurality of elements in the dependency structure matrix; a first conversion module for converting said DSM data set into a Gantt data set representing a time-based sequence of said activities for a Gantt chart visualisation of the DSM data set; a second conversion module for converting said Gantt data set back to a corresponding DSM data set; wherein activity interdependency information is retained during conversion by both said first and second conversion modules.

According to another aspect, the present invention provides a method for manipulating a time-sequenced series of interdependent and dependent activities comprising: receiving a DSM data set representing a dependency structure matrix defining a plurality of activities each having data dependency on other ones of the plurality of activities in the dependency structure matrix; converting said DSM data set into a Gantt data set representing a time-based sequence of said activities for a Gantt chart visualisation of the DSM data set; making changes in said time-based sequence of activities of said Gantt data set that affects an interdependency of said activities; and converting said Gantt data set back to a corresponding DSM data set; wherein activity interdependency information is retained during conversion by both said first and second conversion modules.

Embodiments of the present invention will now be described by way of example and with reference to the accompanying drawings in which:

Figure 1 shows a schematic diagram of the steps in a prior art analytical design planning technique;

Figure 2 shows examples of a dependency structure matrix as known in the prior art;

Figure 3 shows an exemplary process flow sequence of seven tasks having two looped dependencies therein;

Figure 4 shows a DSM representation of the process flow of figure 3; Figures 5a, 5b and 5c show simplified Gantt chart representations of the process flow of figure 3; Figure 6 shows a modified process flow sequence, based on figure 3, but retaining interdependency information suitable for transporting the process flow between the DSM and Gantt chart domains;

Figure 7 shows a Gantt chart representation of the process flow sequence of figure 6;

Figure 8 shows a Gantt chart representation of a process flow modified in the Gantt chart domain from the process flow of figure 7;

Figure 9 shows a consequential change in the process flow sequence of figure 7, consequent on the change made, in the Gantt chart domain, in figure 8; Figure 10 shows a modified DSM arising from the process flow information in figure 9;

Figure 11 shows a computer system for displaying and manipulating process flow sequences in both the DSM domain and in the Gantt chart domain;

Figure 12 shows a process diagram representing a small part of a building design schedule;

Figure 13 shows a DSM representation of the process diagram of figure 12;

Figure 14 shows a Gantt chart representation of the process of figure 12;

Figure 15 shows an alternative Gantt chart representation of the process of figure 12; Figure 16 shows a Gantt chart representation of the process of figure 12 with a delayed activity; and

Figure 17 shows a Gantt chart representation of the process of figure 12 but with additional activities for maintaining interdependency information.

The invention provides an apparatus and method for representing and sequencing interdependent processes in relation to time whilst retaining the interdependency that exists within the process. As such, even though only the forward flowing logic is being used to determine the longest overall duration to complete the process, the backward flowing logic between events is retained ready for ongoing analysis using appropriate methods such as using the DSM manipulation apparatus described in GB 2381627B. This ongoing analysis enables the impact of introducing or removing activities and/or dependencies (whether backward flowing or forward flowing) to be assessed and understood dynamically as the sequence of events proceeds. The complexity of most engineering and construction design processes implemented in a DSM representation and a Gantt chart representation means that it is simply not possible for a person to visualise the overall consequences to the process flow arising from changes made in either the DSM domain or the Gantt chart domain.

Conventional systems for generating Gantt chart visualisations are unable to properly handle backward flowing logic, e.g. that which is required in fully interdependent tasks or activities. Most simply remove the feedback dependencies or are unable to maintain the dependencies in a way such that the full interdependent process flow logic can be passed back from the Gantt chart domain to the DSM domain.

A form of automatic conversion between the two domains is required.

Figure 11 shows a system 110 for displaying and manipulating process flow sequences in both the DSM domain and in the Gantt chart domain. A first conversion module 111 and a second conversion module 112 are provided between a first database 113 and a second database 114. The first database 113 stores a data set in the DSM domain, representing a dependency structure matrix that has a plurality of elements each having data dependency on other ones of the plurality of elements in the DSM. The second database 114 stores a Gantt data set representing a time-based sequence of the activities for a Gantt chart visualisation of the DSM data set. DSM domain database 113 may be associated with a DSM domain display and manipulation module 115 such as described in GB 2381627B. Gantt chart domain database 114 may be associated with a Gantt chart display and manipulation module 116 as known in the art. The expression 'database' is used in a broad context to include any suitable data storage medium, data structure or file structure.

As described herein, full interdependent process flow logic is retained so that it can be passed back from the Gantt chart domain 114 to the DSM domain 113 by modifying the 'real' activities of the DSM that form interdependent loops to obtain: i) shadow activities, referred to herein as 'circuit breaker activities', with all backward flows retained but which are not utilised to calculate the longest path through the process; and ii) the real activities with all forward flowing logic retained (the basis for Gantt chart production) that are used for the purposes of the time sequence calculations.

For illustration purposes, figure 3 shows a very simple sequence of seven activities in which there is looped dependency between activities C and E. In other words, activity C is directly dependent upon the outcome of a predecessor activity B and also directly dependent on the outcome of two successor activities D and E.

Figure 4 illustrates the DSM representation of this process flow. The dependence of activity C on B is shown by filled box 41. The dependence of activity C on activities D and E is shown respectively by filled boxes 43 and 42. The dependence of activity D on activity C is shown by filled box 44. The dependence of activity E on activity D is indicated by filled box 45. It will be apparent that the reverse flowing dependencies appear above the diagonal line of 'X's while the forward flowing dependencies appear below the diagonal line of 'X's.

A dependency strength shown as letter ¹A' may be included in the relevant boxes.

Gantt chart representations of such a series of activities are shown in figure 5. In conventional systems, the looped dependencies are ignored and the time sequence of activities are represented with each activity in the interdependence loop presented sequentially as shown in figure 5a or concurrently as shown in figure 5c. In either case, the backward dependence logic is ignored and lost. Conventional programs or apparatus used to display Gantt charts have no mechanism for retaining the interdependencies which are illustrated schematically in figure 5b by lead lines 51 , 52 extending between the ends of activities D and E respectively and the start of activity C.

If adjustments are made to the Gantt chart (e.g. extending an activity duration, or moving an activity in relation to another activity, the updated information cannot be passed back to the DSM domain in order to re-analyse the process for improving the consequential changes in looped dependencies because in conventional Gantt chart display and manipulation programs or modules the backward dependencies are not held.

Figure 5c shows an alternative representation where the looped dependent activities are displayed concurrently, the interdependencies being indicated by lead lines extending between activity E and the other activities C and D.

Figure 6 illustrates a method for maintaining interdependency information while passing the process flow into and out of the Gantt chart time sequence domain.

Activities C, D and E represent a (looped) series of interdependent activities in the DSM data set lying between a designated first activity (activity B) and a designated second activity (activity F). In other words, the designated first activity (B) is the activity that feeds into a loop and the designated second activity (F) is the activity that feeds from the loop.

With reference to figure 6 (which corresponds to the process flow of figure 3), an 'interdependence start milestone activity¹ 61 is created that depends from the designated first activity (activity B) and is in parallel with the path from the designated first activity (activity B) to the first activity (activity C) in the series of interdependent activities. An 'interdependence finish milestone activity' 62 is created from which the designated second activity (activity F) is dependent and is in parallel with the path from the last activity (activity E) in the series of interdependent activities to the designated second activity (activity F).

For each dependency in the series of interdependent activities (activities C, D and E), a respective 'circuit breaker activity' 63, 64 and 65 is created which connects the start milestone activity 61 to each other activity that has a dependency from that respective activity. In other words, an 'activity C circuit breaker¹ 63 activity is inserted between the interdependence start activity 61 (from which it is dependent) and activity D representing the dependence of D from C. Similarly, an 'activity D circuit breaker¹ 64 activity is inserted between the interdependence start activity 61 (from which it is dependent) and activity E representing the dependence of E from C. Similarly, an 'activity E circuit breaker" 65 activity (from which it is dependent) is inserted between the interdependence start activity 61 and activity C representing the dependence of C from E. The additional looped dependence of activity C from activity D is represented by an additional link from 'activity D circuit breaker¹ 64 to activity C, as well as the link to activity E already described.

The 'interdependence finish milestone activity' 62 is connected to each of the activities (activities C to E) in the series of interdependent activities and to the subsequent designated second activity (activity F). Direct dependencies between each of the activities within the looped series of interdependent activities are removed or disconnected so that all dependencies in the looped series are via circuit breaker activities.

In principle, the interdependence finish milestone activity 62 needs only to be linked to (i.e. dependent from) the longest duration one of the activities (in the example this is activity E) in the series of interdependent activities (activities C, D and E in the example). In order to ensure that this is always the case, it is preferred to link the interdependence finish milestone activity 62 to each one of the activities in the series of interdependent activities between the designated first activity (activity B) and the designated second activity (activity F). In this way, the interdependence finish milestone activity 62 does not finish any earlier than all of the activities in the series.

Each interdependence start activity 61 , interdependence finish activity 62, and circuit breaker activity 63, 64 and 65) is preferably ascribed no duration (or only nominal duration that does not significantly affect the overall timescale of the process flow), no ownership, no associated effort or resource etc and is required only to support the properties of defining successor dependencies. These shadow activities 61 to 65 are preferably associated with coding to render them invisible on a Gantt chart representation.

The production of the process flow 60 of figure 6 is performed by the first conversion module 111 in the system 110 of figure 11 , from a DSM domain data set provided by a DSM database 113, and passed to a Gantt chart domain data set in database 114 for subsequent display and manipulation by a Gantt chart display and manipulation module 116.

Turning now to figure 7, it can be seen how the process flow 60 would be indicated in Gantt chart representation.

The interdependence start activity 61 and each circuit breaker activity 63, 64, 65 are specified as concurrent activities and are specified with a coincident commencement time as well as having zero or nominal duration. Each activity in the series of interdependent activities (activities C, D and E) are specified as concurrent activities, preferably with the same commencement time as each other and preferably with the same commencement time as the circuit breaker activities 63, 64, 65 and the interdependence start activity 61. It will be noted, however, that in view of the interdependence of these activities C, D, E, some flexibility in the relative time positioning thereof while maintaining the allocated dependencies could be allowed without loss of the overall process flow timing and sequence. For example, as shown, activity D is relatively short and could be shifted to slightly later within the overall timespan of activity E. The interdependence finish activity 62 is specified with a zero or nominal duration and positioned at the end of, or later than, the latest finishing one of the series of interdependent activities C, D, E. In the exemplary case of figure 7, this is at the end of activity E.

Circuit breaker activities are thus created as 'shadows' of the real activities that sit within the Gantt chart, they are represented as milestone events preferably with the sole purpose of retaining the backward flowing logic associated with the real activities.

As discussed above, preferably the interdependence start activity 61 , the interdependence finish activity 62 and the circuit breaker activities 63, 64, 65 are given 'invisible' attributes in the Gantt chart representation so that they do not appear nor confuse the user's view of the overall sequence of events. However, their presence and effects will serve to maintain a proper set of dependencies in the module 116 such that if the activity durations and/or relative positions are manipulated within the Gantt chart, the looped dependency information will be preserved and will be available for export back to the DSM domain by the second conversion module 112 (figure 11).

It will be understood that a typical process flow will be vastly more complex than that depicted in figure 6, and may have many hundreds of looped dependencies. Thus, the conversion module 111 is adapted to handle each series of interdependent activities in similar manner.

In the Gantt chart domain, once a change occurs in the activities and/or dependencies within the Gantt chart (such as that in figure 6, which is represented schematically in figure 7), requiring the impact of this change to be understood in relation to the true interdependency in the process, the data is viewed within the DSM domain.

Figure 8 depicts the process flow of figure 7 but with a modification made by the user in which he or she has decided to break the dependency of activity C on activity E (perhaps because in the overall process management it has been realised that this dependency is no longer required or it has been compensated for in other ways). In breaking this dependency, the property of activity C is changed so that it is no longer dependent on 'activity E circuit breaker¹ 65a which has become a dead end as shown in figure 9. This modification is readily exported back into the DSM domain by the second conversion module 112 which can remove the redundant 'activity E circuit breaker¹ activity 65. When viewed in the DSM (as shown in figure 10), the circuit breaker activity 65 property (i.e. the backward flowing dependency) is deleted and so the DSM domain display shows backward dependency (above the diagonal lines of 'X's) only of activity C from D with filled box 43. Comparison of figure 10 with figure 4 shows that the other backward dependency boxes above the diagonal lines have been cleared. Thus, the changes made in the time sequence (Gantt) domain have been correctly exported back to the DSM domain where the simplifying effects of the looped dependency in the DSM domain can readily be seen.

Thus, the function of the second conversion module 112 is first to identify all interdependent activities represented by circuit breakers between a start interdependency activity 61 and a finish interdependency activity 62. Any dead end circuit breakers 65a can be ignored. Interdependent activities (i.e. those with circuit breakers) are therefore identified and the dependencies of the type 'circuit breaker to activity' are re-defined as 'activity to activity'. The start and finish interdependency milestones and circuit breakers are then removed.

It will be understood that the Gantt chart display and manipulation module 116 is provided with a user interface by which amendments, corrections and other manipulation of the sequence of activities can be made, often increasing the complexity of dependencies which will then need to be exported back to the DSM domain in order to create a revised DSM viewable by the user to see the consequences, adverse or otherwise, of the changes made in the Gantt domain. Thus, in a general aspect, the module 116 may provide a means for effecting changes in one or more tasks in a time- based sequence of tasks of the Gantt chart visualisation. In another general aspect, the module 116 may provide a user input means for effecting changes in one or more tasks in a time based sequence of tasks.

For example, a user may wish to examine the effects of changing the start and/or end positions of an activity relative to other activities or changing dependencies of activities, on creating new looped interdependencies that did not exist before the change. These new looped interdependencies can readily be examined in the DSM domain, where the module 115 (such as described in GB 2381627B) may then be used to further manipulate the process. Preferably, the system 110 may be provided as an integrated set of software modules that execute either simultaneously or at the request of a user on a computer system so that the user can switch backwards and forwards between a DSM view and a Gantt chart view of the process flow, readily viewing consequential changes made in either domain.

There now follows an exemplary illustration of application of the computer-based planning tool in the field of building design and construction. Figure 12 illustrates a process diagram 120 representing a small part of a building design schedule, in this example the activities required to design and co-ordinate a ceiling within a building. It is clear from the dependencies between activities that this design problem has interdependencies. For example, the activity 'Electrical Engineer produces lighting layout' (box 122) both depends on and is dependent on 'Mechanical Engineer produces air conditioning diffuser / grille layout' (box 123). Similarly, the activity 'Electrical Engineer produces smoke detector and fire alarm layout' (box 124) both depends on and is dependent on the activity 'Electrical Engineer produces lighting layout' (box 122).

Figure 13 shows a DSM diagram 130 representing this design process and clearly shows the interdependence in the process: four out of six activities are interdependent.

Time-based process definition tools do not allow calculations to be effected on interdependent processes. The Gantt diagram in figure 14 shows a typical computer- generated representation of the process of figure 12, which corresponds with the format of figure 5a. The dependence of task 'Electrical Engineer produces lighting layout' (task numbered 2) on 'Mechanical Engineer produces air conditioning diffuser / grille layout' (task numbered 3) has been ignored as have the relationships of 'Electrical Engineer produces smoke detector and fire alarm layout' (task 4) on 'Electrical Engineer produces lighting layout' (task 2) and 'Fire Engineer produces sprinkler head layout' (task 5) on 'Mechanical Engineer produces air conditioning diffuser / grille layout' (task 3). This has been a necessary step in order to have the Gantt chart perform any date calculations.

In the process of figure 14, the user has arbitrarily decided that 'Mechanical Engineer produces air conditioning diffuser / grille layout' (task 3) will be undertaken after 'Electrical Engineer produces lighting layout' (task 2). In practice this means that the position of air conditioning or ventilation air outlets will be constrained by the position of lights and that they, therefore, may not be in the optimum position. The result of this may be that areas of a space suffer from cold air down-draughts or warm spots with little air movement - most people have experienced the discomfort which results from sitting below a badly positioned air diffuser in a meeting room or restaurant. It could be argued that this is simply a mistake by the user in arbitrarily deciding that 'Mechanical Engineer produces air conditioning diffuser / grille layout' (task 3) will be undertaken after 'Electrical Engineer produces lighting layout' (task 2) and that the two should be reversed (i.e. the wrong dependency has been ignored). However in practice this would mean that the position of lights would be constrained by the position of air diffusers and grilles. The result may be uneven lighting levels across a space which can have undesirable effects such as a drop in productivity in office areas.

So, from the above description it is evident that interdependent activities should be undertaken in parallel and not sequentially. Therefore, the timescale calculated in figure 14 is misleading. The only alternative 'traditional' method of representing the process, which would be as per figure 5c, is shown in figure 15. Whilst this representation gives an accurate timescale for the interdependent problem it does not retain the full set of dependencies and, therefore, is unable to accurately calculate the effects of delay in the project. This can be seen in figure 16 where the start of activity 'Architect produces layout of ceiling grid' (task 1) is delayed. The overall timescale is correctly impacted but, because dependencies have been ignored, the two activities 'Mechanical Engineer produces air conditioning diffuser / grille layout' (task 3) and 'Electrical Engineer produces lighting layout' (task 2) are no longer concurrent.

The Gantt representation in figure 17 shows the process with the inclusion of 'circuit breaker' activities and the retention of interdependence. The two activities 'Mechanical

Engineer produces air conditioning diffuser / grille layout' (now task 8) and 'Electrical

Engineer produces lighting layout' (now task 7) are shown being undertaken concurrently since they are known to be interdependent. They would remain concurrent even with the delay to activity 'Architect produces layout of ceiling grid' (task 1 ). So, the dependencies are retained in this representation and the timings of all activities are accurate (unlike in figures 14, 15 and 16).

We consider what this representation of the process means in practice. How does the mechanical engineer start his design without the electrical engineer having done his design? The electrical engineer may be wondering the same thing about his own work, since the mechanical engineer's design has not done his design. The design of both can only commence with a conversation between them. This dialogue must continue throughout the period of both activities until a point in time where a co-ordinated design solution is agreed and each activity can be completed safe in the knowledge that the output will be that co-ordinated solution. In practice this could mean that neither the lights nor the diffusers are in the optimum positions, but it does mean that any undesirable effects such as down-draughts or uneven lighting levels are avoided.

In a typical building design project there are numerous cases similar in nature to the example described here and these interdependent processes cause a wide range of tangible problems.

In one example, the design solution will end up 'over-engineered'. Structural elements, such as foundations, are much larger than required because their sizes are calculated prior to the weight of large equipment being determined. More concrete and reinforcement is used than is necessary, with resulting cost and environmental impacts. Plant rooms and service shafts are larger than required because their sizes are calculated prior to pipe, duct and electrical cables being selected. More space is dedicated to plant meaning less is available for other purposes: the most obvious effect is in office spaces where rent is charged per sq. m of usable space.

In another example, the design solution is not co-ordinated. Pipes and ducts do not line up with penetrations which have been left for them. Pipes and ducts are re-routed during the construction process, taking more time than expected and using more material than required. An exemplary result might be that a pipe is reconfigured so that a valve is no longer in the position expected and hence cannot be accessed properly for maintenance purposes. Another consequence might be that window positioning clashes with external features such as a fire escape stairway. A result is a lack of quality and usability of a building.

In another example, the design is completed late. This can result in delays to a construction project with resulting cost penalties to the builder, or results in the builder trying to generate a design solution themselves so that their construction schedule is maintained.

The present invention provides a computer-based tool that enables the user to better coordinate the many tasks required in a complex undertaking. By enabling the user to manipulate and display the process both in the DSM domain and in the time domain (Gantt chart), the user is better able to comprehend the complexity of the process and the consequences of manipulation and rescheduling of tasks.

The improvement in the computer-based tool arises not least by the provision of a first conversion module for converting a DSM data set into a Gantt data set representing a time-based sequence of said activities for a Gantt chart visualisation of the DSM data set in which the interdependency information is retained within the Gantt data set by use of the creation of interdependence start activities and interdependence finish activities and circuit breaker activities. This enables the data sets representing DSM views of the activities and Gantt chart type views of the activities to be readily transferred between applications without loss of functionality.

Other embodiments are intentionally within the scope of the accompanying claims.

Claims

1. Apparatus for assisting in the manipulation of a time-sequenced series of interdependent and dependent activities comprising: a database for receiving a DSM data set representing a dependency structure matrix defining a plurality of activities each having data dependency on other ones of the plurality of activities in the dependency structure matrix; a first conversion module for converting said DSM data set into a Gantt data set representing a time-based sequence of said activities for a Gantt chart visualisation of the DSM data set; and a second conversion module for converting said Gantt data set back to a corresponding DSM data set; wherein activity interdependency information is retained during conversion by both said first and second conversion modules.

2. The apparatus of claim 1 further including: means for effecting changes in one or more tasks in a time-based sequence of tasks of the Gantt chart visualisation.

3. The apparatus of claim 1 further including: display means for displaying a Gantt chart visualisation of the second data set; and user input means for effecting said changes in one or more tasks in a time-based sequence of tasks.

4. The apparatus of claim 1 in which the first conversion module is adapted to generate the Gantt data set by: identifying a series of interdependent activities in the DSM data set disposed between a first activity and a second activity; inserting an interdependence start milestone activity depending from said first activity and in parallel with a path to an activity in said series; inserting an interdependence finish milestone activity from which the second activity is dependent and in parallel with a path from another activity in said series; for each dependency in said series, connecting each activity in said series to said start milestone activity via a circuit breaker activity representative of each other activity from which the respective activity depends; and connecting at least a longest lasting activity in said series to said finish milestone activity.

5. The apparatus of claim 4 in which the first conversion module is further adapted to generate the Gantt data set by disconnecting each direct link from each activity in said series to another activity in said series.

6. The apparatus of claim 4 in which the interdependence start activity and each circuit breaker activity are specified as concurrent activities.

7. The apparatus of claim 6 in which the interdependence start activity and each circuit breaker activity are specified with a coincident commencement time.

8. The apparatus of claim 7 in which the interdependence start activity and each circuit breaker activity are specified with zero or nominal activity duration.

9. The apparatus of claim 7 in which the series of interdependent activities are each specified with a coincident commencement time, being the same coincident commencement time as the interdependence start activity and each circuit breaker activity.

10. The apparatus of claim 9 in which the interdependence finish activity and the second activity are each specified with a commencement time coincident with, or later than, the latest ending time of the interdependent activities.

11. A method for manipulating a time-sequenced series of interdependent and dependent activities comprising: receiving a DSM data set representing a dependency structure matrix defining a plurality of activities each having data dependency on other ones of the plurality of activities in the dependency structure matrix; converting said DSM data set into a Gantt data set representing a time-based sequence of said activities for a Gantt chart visualisation of the DSM data set; making changes in said time-based sequence of activities of said Gantt data set that affects an interdependency of said activities; and converting said Gantt data set back to a corresponding DSM data set; wherein activity interdependency information is retained during conversion by both said first and second conversion modules.