An event-driven approach with makespan/cost tradeoff analysis
for project portfolio scheduling
, Brian Wang
, James Dong
, Kuo-Cheng Ku
Institute of Industrial Management, National Central University, Chung-Li, Taiwan 320, ROC
e-Business Integration Section, Taiwan Semiconductor Manufacturing Company Ltd., Hsin-Chu, Taiwan 300, ROC
Department of Industrial Engineering & Management, Ming-Hsin University of Science & Technology, Hsin Chu, Taiwan 304, ROC
Received 7 November 2003; accepted 24 November 2005
Project Portfolio Management (PPM) has become increasingly important in managing multiple projects simultaneously. However, during
execution, the project portfolio is associated with considerable uncertainty that leads to resource contention among projects and schedule
disruptions. Regarding the need to revise a schedule when unexpected events occur, we adopt an event-driven approach to develop a tradeoff
decision framework for project portfolio scheduling and rescheduling. In the framework, High Level Petri nets, Activity-Based Costing and
Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) are applied in sequence to generate feasible schedules, estimate their
makespan and costs, and select the best compromise schedule. This framework is advantageous in the evaluation of scheduling performance from a
multi-criteria perspective and the incorporation of both objective and subjective measurements in the decision process.
# 2006 Elsevier B.V. All rights reserved.
Keywords: Project portfolio; Event-driven scheduling; Makespan/cost tradeoff; High Level Petri nets; Activity-Based Costing; TOPSIS
How to determine, manage and balance the right mix of
projects is crucial to any organizations operating in a multi-
project environment. Recently, Project Portfolio Management
(PPM) has become prevalent; it is expected that multiple
projects under a single management umbrella will deliver
beneﬁts that will not be possible if the projects were managed
independently [1–4]. Furthermore, while multiple projects run
in parallel and demand the same resource simultaneously,
frequent conﬂicts are inevitable [5,6].
Strategically, PPM aims to maximize the value of the
projects as a whole, balance the portfolio relative to reward and
risk, and align projects to business objectives . The tactical
implementation of PPM seeks to evaluate the merits of projects
and thus facilitate budget allocation decisions, manage project
life cycles, align resource demand with resource availability,
and measure their level of contribution [8,9]. Operationally,
PPM organizes a series of projects into a single portfolio of
reports that capture project timelines, accomplishments,
resource consumption, costs, and other critical factors .
With this comprehensive framework, executives can then
regularly review entire portfolios, spread resources appro-
priately and adjust projects to produce the highest returns.
According to [11,12], PPM is a dynamic process where
active projects are constantly reviewed and modiﬁed and new
initiatives are evaluated, selected and prioritized. During this
process, resources are coordinated and reallocated among
projects while contradicting schedule targets would be rear-
ranged to make resources sufﬁce and maintain equilibrium
within the portfolio [13–15]. With timely information about the
status of the portfolio and resource availability, the focus is
placed on resource interdependencies and the mutual compat-
ibility between projects at the aggregate level.
PPM can be regarded as a management system involving
portfolio evaluation (approaches and methods), decision-
making (gates and reviews), and support functions (information
management and resource allocation) . Several Project
Portfolio Management Systems (PPMS) have been proposed for
the development of decision support systems. The system may
incorporate project selection, resource allocation, risk manage-
ment, priority management and ongoing control , project
Computers in Industry 57 (2006) 379–397
* Corresponding author. Tel.: +886 3 4229524; fax: +886 3 4258197.
E-mail address: firstname.lastname@example.org (H.-P. Kao).
0166-3615/$ – see front matter # 2006 Elsevier B.V. All rights reserved.