New Placement Strategy for Buffers in Critical Chain

Conference paper
Part of the Advances in Intelligent Systems and Computing book series (AISC, volume 236)


With the introduction of Critical chain by Goldratt in 1997, there has been a lot of research in the field of resource constraint project scheduling problems (RCPSP) and Buffer Sizing techniques. This paper suggests a Buffer management technique which aims at reducing the make span time yet maintaining the stability of the project. In the theory of CCPM it is suggested to reduce the duration of all the activities by half to remove the excess safety time in each activity. The trimmed duration is collected and made available at the end of the project in the form of project buffer which could be used if the project gets delayed. Another buffer called the feeding buffer is added whenever a noncritical chain joins a critical chain. This increases the project duration if the slack of the last activity in the feeding chain is smaller than the feeding buffer. In such cases, this paper suggests the division of the project buffer into parts, fitting each part at the junction of critical and noncritical chains so that the delay occurred because of addition of feeding buffer can be utilized and the duration of project buffer is shortened. The use of the proposed technique has reduced the project duration by a significant value.


Buffer Feeding buffer Project buffer Buffer sizing technique CCPM 


  1. 1.
    Reference for Business Encyclopedia of Business, 2nd ed. Per-Pro Program Evaluation and Review Technique (PERT)
  2. 2.
    Badiru, A.B.: Activity resource assignments using critical resource diagramming. Proj. Manage. J. XXIV, 15–21 (1993)Google Scholar
  3. 3.
    Gemmill, D.D., Tsai, Y.-W.: Using a simulated annealing algorithm to schedule activities of resource constrained projects. Proj. Manage. J., pp. 8–20 (1997)Google Scholar
  4. 4.
    Goldratt, E.: Critical Chain, 1st edn. North River Press, Barrington (1997). ISBN 0-88425-153-6Google Scholar
  5. 5.
    Steyn, H.: An investigation into the fundamentals of critical chain project scheduling. Int. J. Proj. Manage. 19(6), 363–369 (2001)CrossRefGoogle Scholar
  6. 6.
    Steyn, H.: Project management applications of the theory of constraints beyond critical chain scheduling. Int. J. Proj. Manage. 20(1), 75–80 (2002)CrossRefGoogle Scholar
  7. 7.
    Xie, X, Yang, G., Lin, C.: Software development projects IRSE buffer settings and simulation based on critical chain. J .China Univ .Posts Telecommun. 17(Suppl 1), 100–106 (2010)Google Scholar
  8. 8.
    Tukel, O.I., Rom, W.O., Eksioglu, S.D.: An investigation of buffer sizing techniques in critical chain scheduling. Eur. J. Oper. Res. 172(2), 401–416 (2006)Google Scholar
  9. 9.
    Long, L.D., Ohsato, A.: Fuzzy critical chain method for project scheduling under resource constraints and uncertainty. Int. J. Proj. Manage. 26(6), 688–698 (2008)Google Scholar
  10. 10.
  11. 11.
    Bevilacqua, M., Ciarapica, F.E., Giacchetta, G.: critical chain and risk analysis applied to high-risk industry maintenance. A case study. Int. J. Proj. Manage. 27(4), 419–432 (2009)Google Scholar
  12. 12.
    Herroelen, W., Leus, R.: On the merits and pitfalls of critical chain scheduling Original Research Article. J. Oper. Manage. 19(5), 559–577 (2001)Google Scholar
  13. 13.
    Hazir, O., Haouari, M., Erel, E.: Robust scheduling and robustness measures for the discrete time/cost trade-off problem. Eur. J. Oper. Res. 207, 633–643 (2010)Google Scholar

Copyright information

© Springer India 2014

Authors and Affiliations

  1. 1.University CollegeChunni KalanIndia
  2. 2.Department of MathematicsPunjabi UniversityPatialaIndia

Personalised recommendations