An Integrated Design Task Management Approach forProduct Development Lifecycle

Wei HeSingapore Institute of Manufacturing

Technology71 Nanyang DriveSingapore 638075

Singaporewhe@SIMTech. a-star. edu. sg

Ivan Boon Hong LeeBLC Solutions Pte Ltd

iHUB #02-159 Jurong Town Hall Road

Singapore 609431ivanlee@ blcsolutions. com

Eng Wah LeeSingapore Institute of Manufacturing

Technology71 Nanyang DriveSingapore 638075

Singaporeewlee@ SIMTech. a-star. edu. sg

Abstract-Product design is the most critical activity forinnovation and value-adding in a product developmentlifecycle. Product design task management is animportant feature of design frameworks. A properdesign task management solution can definitely increasethe design process efficiency. This paper presents anintegrated approach for managing design tasks, designercapacities, task execution and monitoring in productdevelopment lifecycles. In the proposed approach, designtasks are associated directly with product design data.Each designer's capacity is synchronized and updatedautomatically during design task creation andassignment. Design tasks are routed to assigneddesigners, and task execution, progress and effort spentby designers can be automatically monitored, controlledand tracked. The proposed design task managementapproach can be seamlessly integrated with theupstream and downstream activities of a productlifecycle in terms of its processes and information needs,leveraging on workflow/lifecycle technology. Developedas part of an enterprise system and implemented in thedesign department of a local mould making company, ithas shown that the proposed approach can significantlyimprove the efficiency and effectiveness of design taskmanagement, and thereby facilitating the design processin the company.

I. INTRODUCTION

Product design is critical in product developmentlifecycle. 70 percent of product cost throughout a productlifecycle is determined by decisions made at the designphase although design itself accounts for only 5 percent ofthe total costs under traditional cost accounting methods [1].Product design task management is an important feature ofdesign frameworks. A design task is a set of steps leadingfrom one set of data to another. For example, in the molddesign domain, a task may involve the layout of a moldbased on the plastic part specifications, creation of detaileddesign modules using design authoring tools and use ofsimulation to analyze the molding process. Proper designtask management and tracking can significantly facilitate theproduct design process itself. As products become morecomplex, with ever shorter time-to-market demands andinvolving experts from different disciplines who aregeographically dispersed, the effective management,

assignment, tracking and monitoring of design tasks anddesigner capacity become highly critical.

This paper begins with an introduction, followed by theinvestigation of issues related to product design taskmanagement throughout a product development lifecycle.To address these issues, an approach for product design taskmanagement that can be seamlessly integrated with productdesign information and related process is proposed andpresented in Section 3. Section 4 describes the developmentand implementation of a prototype system in an industrialcompany. Finally, the paper concludes with the researchfindings in Section 5.

II. PRODUCT DESIGN TASK MANAGEMENT

John W. Hagerman summarized that design taskmanagement involves task creation (building a task tree),task resolution/assignment (select tools and data) andexecution (running the tools) [2]. Product specification isanother important factor that needs to be considered indesign task management. It is a science to create tasks, butthe principles are very simple. Current applications aremanual in execution. The task creation should be based onthe product specification, requirements, constraint ofavailable resources and complexity of product design. Theimmense volume of information in product design to bemanaged and monitored is more than any single individualcan handle. It therefore makes sense to reduce the taskcomplexity of product design by decomposing it intosmaller, more tractable tasks. First, the dependency of tasksis determined. Next, tasks are scheduled to follow thedependencies. Finally, tasks are parallelized if possible,making the most efficient use of available resources. Eachdesign task creates design data in a certain form as part of aproduct design, while all the design tasks combined willgenerate all the design data required to finalize the overallproduct design. Task assignment is a function of designtasks, the resources (e.g. designers) and their capacity andcapability. Proper management of design resources and theircapability and capacity is also important for task assignmentand execution. Task execution is a process for the assignee(designers) to perform the assigned tasks and to create theproduct design. Normally execution should follow apre-defined process (a policy if not an explicitly definedprocess in a company) in order to manage the design, designreview and design release processes well. During thisprocess, the status and progress of an assigned task should

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be fed-back to the design supervisor for tracking,monitoring and control.

Design task management normally involves such factorsas design task, design resources (i.e., designers and theircapability and capacity), product specification, productdesign data as well as task execution and monitoringprocess, as illustrated in Fig. 1. In the traditional design taskmanagement approach, the design task is usually the keyfactor in the central position associated with other factors.Among those factors, there is normally no direct interactionwith each other. Even their associations with a design taskare also very loose with little data level commutation andcommunication.Few relevant research works are found in this area but it

is attracting more researchers' attention. John and Stephenstudied the task schema and its effects on task management[2]. The task schema has been shown to be very useful fortask creation, but less than ideal for task resolution, i.e., theselection of tool and data resources to be used in execution.The Taskmaster system has been reported by Bellotti et alwhich recasts email as task management and embedstask-centric resources directly in the client [3]. The studyfocusing on task assignment and routine shows how userstudies conducted with "live" email data over a two-weekperiod revealed the value of a task-centric approach to emailsystem design and its potential benefits for overloadedusers. Federico Garcia and Roberto Moriy6n proposed theWf-ATOMS, a framework for the specification andmanagement of workflows, where its engine is integrated ina multi user and distributed task management system [4]. Aworkflow engine is used to distribute the tasks that areactually the activities of the workflow. The work mainlyfocused on modeling processes while user capacity is notconsidered. Another research was reported [5] for designtask definition and execution in which state-space controltheory is used to model coupled, concurrent design tasks andto predict and control the stability and convergence rate ofthe design tasks. The generalized model can determine thevolume of work remaining for each design task at everystage of iteration, and predict the number of iterationsneeded before all the tasks are completed. It has been usedfor the design of a printed circuit board burn-in chamber.There are some other research works reported[6][7][8][9][10][11][12]. However, all these researchesfocus on only particular aspects of design task managementand execution.

In the market, there are currently a number of commercialcompanies providing solutions for design task creation,assignment, monitoring and management. This includesProjectLink from PTC, SMARTEAM from Dassault Systemand TeamCenter from EDS etc.. There are also some othercommercial products that are usually used for general taskmanagement, such as Microsoft Project from Microsoft andLotus from IBM. However, all the solutions can onlyaddress partial aspects of all the factors involved in productdesign task management. For instance, PTC's ProjectLinkwhich is useful for managing product development projects,provides functions for task creation, assignment andtracking. However, the designers' capacities are notmanaged and synchronized automatically. In addition, thetask progress and functions for tracking and capturing

efforts are not fully automated and integrated with otherfactors.

Fig. 1. Traditional design task management and key factors involved

For the factors involved in product design taskmanagement, i.e., product specification, design tasks, designresources and task execution process as shown in Fig. 1,there should be tight interactions among them in order toenable an efficient and effective product design process.However, as discussed above, there is so far no proper wayreported that can integrate these factors together efficientlyat the level of data and process during design task creation,assignment and execution. This implies that there is nodirect association among those factors. For example, thedesign data generated by a design task has no directassociation with the task and its progress. In addition, adesigner's capacity is normally managed manually ratherthan being automatically synchronized and updated with theassignment and execution of tasks in real-time. A designtask is usually considered as the most important factor intraditional task management. However in the product designand development environment, product design data shouldbe the most critical factor among all the factors. The priorarts do not describe any association or integration betweendesign tasks and the product design data. The definition ofdirect association or integration here implies a specificobject model for exchanging information at the data andprocess level.

In summary, the issues and challenges in design taskmanagement are identified as follows:* A lack of integration/association among the various

factors means that the management and execution ofdesign tasks cannot be performed as a whole.Specifically, there is no integration or associationbetweeno the design tasks with the product specificationo a task and the design data generated from ito the task execution process, design resource used and

its capacity and capabilityo the task execution process and the product design

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review and release process* The product design itself should eventually be the key

outcome of design task management rather than tasksthemselves.

* Design task management should be effectively integratedwith product development lifecycle processes.

III. PROPOSED INTEGRATED PRODUCT DESIGNTASK MANAGEMENT APPROACH

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An approach for design task management is proposed toaddress the issues and challenges as discussed in the lastsection. The scenario can be illustrated as shown in Fig. 2. outegnJ Cmlt

Fig. 3. Proposed general design task management process

Fig. 2. Integrated Design Task Management

As a final target of product design, the design data is thekey factor that is supported by all others in the proposeddesign task management framework. Theworkflow/lifecycle engine as shown in the Fig. 2 acts as thepivot for all the factors in the framework. Any standardworkflow/lifecycle engine that supports programmableactivity can be adopted in this approach. The generalprocess of the proposed design task management approachis briefly illustrated in Fig. 3. The scenario begins with therelease of a confirmed design job from the upstream salesprocess to a design department. It covers activities such asdesign task creation, assignment, task release, designprocess, task execution, tracking and monitoring. It mayalso involve the reassignment of tasks, until the finalcompletion of the design job. Each activity has interactionwith product design specification, design data and designercapacity. Since it is closely related to the design process,designers, product specification and design data, theproposed design task management approach is differentfrom traditional project management and task managementsystems. Each activity is further elaborated in the followingsections.

Task creation: Product design can begin when theproduct specification has been finalized and a confirmedorder is released to the design department. Design tasks arecreated and defined by a design supervisor based on theproduct specification. Design tasks are represented as a treestructure where the root of the tree associates directly withthe product and its specification. Each design task is definedwith a planned start time, a planned end time and theplanned effort. The planned start time and end time specifythe task duration while the planned effort specifies theestimated effort needed to perform the task.Task assignment: The defined design tasks are assigned

to the respective designers by a design supervisor. Eachdesigner's availability and capacity are shown by a workload capacity profile over a period of time. The designer'sdaily work load capacity is represented as a series ofpercentage numbers where "0%" means no work load while"100%" indicates a fully loaded day. It is possible that thepercentage may exceed 100%. In this case, a designer isexpected to work overtime or will be overloaded for the day.A designer's available capacity can be easily obtained fromhis daily work load capacity. The latter is calculated basedon the tasks assigned/released and his official workinghours. There are two kinds of daily work load capacity for adesigner: a) the planned capacity, which is computed fromthe planned task load and the official daily working hours;and b) the actual capacity, which is based on the actualeffort captured in real-time from the task execution processand the designer's official daily effort. A designer's dailywork load capacity can be affected by some non-designrelated activities, such as training, personal leave andmeetings; these can be manipulated and defined as well.Task release: After a task has been assigned to a suitable

designer, it can be released by the design supervisor forexecution. When a task is released, a design holder object iscreated containing the preliminary design data andinformation generated from the task details. The designholder object holds the design data created by the assigneddesigner, and is directly linked to the design task itself. Thedesign holder object is workflow/lifecycle-controlled andreflects the task status throughout its execution. Theassignment and release of a task to a designer will affect hiscapacity profile. It is thus updated with the planned startdate, planned end date and planned effort for the task. A

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capacity engine has been designed to perform this function.It can calculate the daily effort needed according to thedesigner's calendar and the planned duration of the task.The designer's daily work load capacity profile is thenupdated automatically based on his existing capacity profile.An alert is issued if the planned daily loading capacityexceeds the official daily work load capacity of the designer.Task execution monitoring and tracking: Upon its

release, the task and its linked design holder object arerouted to the designer by the workflow/lifecycle engine. Asmentioned previously, the design holder object is acontainer that holds the design data created by the designer.The execution process, driven by the workflow/lifecycleengine, automatically captures the time when the designerstarts and when he completes the task. The actual start time,actual end time and actual effort spent daily on the task canbe recorded. Consequently, the task status and the designer'scapacity profile can be updated accordingly. The designer'swork load capacity profile is designed to show the actualloading (history) before the current day, while the plannedloading profile is shown after that day (future). This designenables the supervisor to monitor and analyze the taskperformance and resource utilization effectively. As thedesign holder object goes through the design, review andredesign processes, the actual effort spent is accumulatedand updated until the design data held in the design holderobject is approved and released to the next stage.Task reassigned: Under certain circumstances, a design

task may need to be reassigned to another designer after ithas been released or under execution. In this case, thecurrent task execution is terminated and a new design taskcreated. The new task inherits its details from the terminatedtask and the progress made so far. Its planned effort is thenadjusted for the remaining work to be done. Thereafter, thenew task is ready to be assigned to another designer andreleased for execution following the same logic as describedpreviously. The work load capacity profiles of the respectivedesigners are also updated accordingly.

Fig. 4 summarizes the proposed design task managementapproach and its integration with the product developmentlifecycle. As a product evolves through its lifecycle, theplanned design tasks are created and assigned to designersduring the design stage. A design holder object is generatedafter a design task has been released to hold the design datathat results from the task execution process. As a designholder object goes through its own lifecycle, it keepsinteracting with the design task, updating the designer'swork load capacity profile. Eventually, the final designproduced by all the design tasks is linked with the productobject. It can then be released to the downstream businessprocesses.With the proposed approach, all the important factors in

design task management, including the design tasks,designer resources and their capacities, product, design dataand the execution processes, can be truly associated andintegrated with each other at the data and process levels. Thecreation, assignment and execution of tasks, theinterpretation of product specifications as well as the designactivity are all performed as a whole. In addition, theproposed approach has the capability to adapt to differentdesign cultures in any company due to the flexibility and

ease of configuring the workflow/lifecycle. The advantagesof the proposed approach are briefly summarized below.

1) Full integration/association of the design resources,capacity profiles, design data, product specificationsand design tasks from planning through execution

2) Integration at the data and process levels3) An adaptive task execution process enabled by

workflow/lifecycle technology4) The design task management process is fully

integrated with the overall product design anddevelopment process

5) Each designer's capacity and actual effort spent on atask can be captured and updated in real-timedynamically

6) Product specifications can be routed to a designdepartment by the underlying workflow/lifecycleengine, and are directly associated with the designtasks.

Fig. 4. Proposed approach and its integration with product lifecycle

With the proposed approach, a previously manual andexperience-based design task management and executionprocess can now be transformed into an integrated,automatic and knowledge-based process which is far moreefficient.

IV. PROTOTYPE AND IMPLEMENTATION

The proposed design task management approach has beentested with a prototype system. The prototype system hasbeen built on the Enterprise Business InformationManagement System model (EBIMS) based on a PDMFramework [13]. The EBIMS model streamlines themanagement of information of key business processes,including quotation, sales order processing, design,planning, scheduling, and production to delivery. Built on aPDM framework to integrate the different disciplines, themulti-layered EBIMS architecture provides capability formanaging key business processes with a single unified dataand process model so as to achieve streamlined processesand data integrity throughout the entire product

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development lifecycle, and hence improving enterpriseefficiency. The prototype system has been developed in Javaas a web-based application based on PTC's Windchillsystem and deployed in the Apache-Tomcat environment.Users can access the system via an Intranet or the Internetthrough a firewall. More details of the prototype system canbe found in [13].The system has been deployed in a mid-sized mold

making company. Fig. 5 shows the business scenario, whichincludes the key business processes for mold development.As shown in Fig. 5, the prototype system covers sales,design, planning, manufacturing, purchasing, productiontracking and shipment processes. Engineering changeprocesses are also considered. Although the implementationof the system in the company was intended to achievevarious objectives [13], this paper focuses on the study andanalysis of product design task management. Prior toimplementing the prototype system, the company did nothave any enterprise information system support. Productdesign tasks are managed manually by a design supervisor,who had to plan for the different modules of a mould to bedesigned and then to assign them to the different designersin the design department. The management of eachdesigner's capability as well as the monitoring and controlof design tasks were performed manually. The design datacreated by the various designers were submitted to thesupervisor for review and integration. The final designwould then be released to the planning and fabricationdepartments. The manual process involved a lot of verbalcommunication and paper work to ensure that the relevantinformation was properly synchronized and monitored,especially when there were changes to handle, rendering iterror-prone.

Shiprnt PS: Product Structure

Fig. 5. Implementation business scenario ofthe prototype

With the prototype system providing advanced features tosupport product design task management, the designsupervisor can now manipulate the design tasks, such ascreation, assignment, release and monitoring, with greatease. As all the required information is synchronized and

readily accessible in real-time, efficiency is increased anderrors are reduced. Fig. 6 shows a sample user interface inthe prototype system displaying the designer capacityprofile. Analysis shows that the prototype system canimprove a company's overall business efficiencysignificantly, partly because the streamlined designprocesses are well supported by the proposed design taskmanagement approach. The overall reduction of cycle timeof the key business processes is about 20-50%, of whichsales, planning and shipping can expect about 50%improvement, and about 20% improvement in design andmanufacturing.

Loading Capacity Profile:

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Fig. 6. Sample GUI for product design task management

Currently the prototype system has been commercializedby a local company offering enterprise system businesssolutions.

V. CONCLUSION

In a product development enterprise, design is verycritical for creating innovation and value-add to its products.Proper design task management can facilitate the productdesign and design process. Design task managementinvolves product specification, design task, designresources, task execution process and design data. Thesefactors interact closely with each other. Currently there is alack of an efficient way to integrate them, especially at thedata and process levels in order to manage and execute thedesign tasks effectively. The currently available solutionsare usually targeted at specific aspects of the various factors,and the processes are loosely coupled and manual. Thispaper deals with the issue by proposing an integrated designtask management approach within the product developmentlifecycle. Workflow/Lifecycle technology is employed toautomate the processes of routing design tasks, trackingdesign status and synchronization of information amongthose factors involved in design task management.Additionally it can integrate the product design and releaseprocess with the overall product development lifecycle.Each design task can be planned and assigned to a suitabledesigner. It is then directly associated with the design datacreated by the designer. The progress status of each task andthe designer's capacity profile are managed, tracked andsynchronized dynamically. A prototype system has beenimplemented based on the proposed approach and deployedin a local mould making company. The result shows adefinitive improvement in the efficiency and effectiveness

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of design task management in the design stage of a productdevelopment lifecycle.

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and Data Selection in Task Management", 33rd DesignAutomation Conference, DAC 96 - 06/96 Las Vegas,NV, USA, 1996

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[4] F. Garcia, and R. Moriyon, "Distributed TaskManagement by Means of Workflow Atoms", SADIOElectronic Journal of Informatics and OperationsResearch, vol. 3, no. 1, pp. 23-32, 2000

[5] K. L. Ong, S. S. G. Lee, and L. P. "Khoo, Modellingand Controlling Coupled, Concurrent Design TasksSubjected to External Influences", InternationalConference on Engineering Design ICED 03Stockholm, Augest 19-21, 2003

[6] M. Gupta, and K. Galloway, "Activity-based costing/management and its implications for operationsmanagement", Technovation, 23, pp.131-138, 2003

[7] H.C.W.Lau, S.K.Tso, and J.K.L.Ho, "Development ofan intelligent task management system in amanufacturing information network", Expert SystemsWith Applications, 15, pp. 165-179, 1998

[8] R. Gelbard, N. Pliskin, and I. Spiegler, "Integratingsystem analysis and project management tools",International Journal of Project Management, 20,pp.461-468, 2002

[9] Z. Kovacs, J-M Le Goff, and R. McClatchey, "Supportfor product data from design to production", ComputerIntegrated Manufacturing systems, Vol.11, No. 4, p.285-290, 1998

[10] Seidmann, and A. Sundararajan, "The effects of taskand information asymmetry on business processredesign", Int. J. Production Economics, 50,pp.117-128, 1997

[11] N. Baker, A. Bazan, et al. "Workflow management inthe assembly of CMS ECAL", Computer PhysicsCommunications, 110, pp.170-176, 1998

[12] E. Okudan, S. G. Bilen, and X. 1. Wu, "GenderOrientation of the Deign Task: Product Domain andFamiliarity Issues", International Conference onEngineering Design, ICED 03 Stockholm, August19-21, 2003

[13] W.He, Q. F. Ni, and B. H. Lee, "Enterprise BusinessInformation Management System based on PDMFramework", 2003 IEEE International Conference onSystems, Man & Cybernetics (SMC2003), 5-8 Oct2003, Hyatt Regency Hotel, Washington, D.C., USA,SMC 2003 Conference Proceedings, pp. 1475 - 1480,Omnipress, 2003.

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