Perbandingan Kinerja Pendekatan Simulasi dan Analitis pada Kasus Perhitungan Dampak Konsumsi Float Aktivitas Nonkritis dalam Penjadwalan Proyek
DOI:
https://doi.org/10.5614/jts.2007.14.2.2Keywords:
Waktu ambang, PNET, Transformasi Rosenblatt, Regresi, Simulasi Monte Carlo.Abstract
Abstrak. Tulisan ini membandingkan hasil perhitungan menggunakan pendekatan simulasi dan analitik dampak konsumsi waktu ambang aktivitas nonkritis terhadap skedul dan biaya proyek. Dasar teori yang digunakan untuk analisis adalah teori reliabilitas yang populer dikombinasikan dengan beberapa pendekatan seperti probabilistic network evaluation technique (PNET) dan transformasi Rosenblatt. Kedua pendekatan menghasilkan kesimpulan bahwa pengunduran aktivitas nonkritis meski belum melebihi waktu ambang total yang dimiliki tetap berpengaruh negatif terhadap jadwal dan biaya proyek. Secara probalistik konsumsi waktu ambang yang bertambah mengakibatkan waktu penyelesaian proyek bertambah yang pada gilirannya meningkatkan biaya total proyek. Hasil perbandingan menunjukkan meski tidak ada perbedaan yang signifikan di antara keduanya, dalam beberapa hal pendekatan analitik berkinerja lebih baik daripada pendekatan simulasi dalam kekonsistenan menjelaskan hubungan yang terjadi antara jadwal, biaya, dan konsumsi waktu ambang.Abstract. This paper compares the computational results of using simulation and analytical approaches on the impact of float consumption on the total project cost and schedule. The base theories employed for analysis are wellknown reliability theories combined with approximation methods such as probabilistic network evaluation technique (PERT) and Rosenblatt transformation. The two approaches arrive at a conclusion that delay in an noncritical activity despite not exceeding total float remains to severely affect the project schedule and cost. Probabilistically, an increase in float consumption escalates the time completion of project which in turn increases the total project cost. The comparison results exhibit that although substantial difference is not observable, in
some respects the analytical approach outperforms the simulation one in terms of consistency of explaining the relationship among schedule, cost, and float consumption.
References
Ahuja, H.N., et al., 1994, "Project Management: Techniques in Planning and Controlling Construction Projects" , 2nd. Ed., John Wiley & Sons, New York.
Ang, A.H-S., Tang, W.H., 1982, "Probability Concept in Engineering Planning and Design" , Vol. II: Decision, Risk and Reliability, John Wiley & Sons, New York.
Cox, M.A.A., 1995, "Simple Normal Approximation to the Completion Time Distribution for a PERT Network" , International Journal Project Management, Vol. 13, No.4, 265-270.
Devore, J.L., 1988, "Probability and Statistics for Engineering and the Sciences" , 2nd. Ed., Thomas Nelson, Melbourne.
Gong, D., Rowings Jr, J.E., 1995, "Calculation of Safe Float Use in Risk Analysis Oriented Network Scheduling" , International Journal of Project Management., Vol. 13, No. 3, 187-194.
Griffs, F.H. (Bud), Christodoulou, 2000, "Construction Risk Analysis Tool for Determining Liquidated Damages Insurance Premiums: Case Study" , Journal Construction Engineering Management, Vol. 126, No. 6, 407-413.
Ioannou, P.G., Martinez, J.C., 1998, " Project Scheduling using State-Based Probabilistic Decision Networks" , Proceeding of the 1998 Winter Simulation Conference, Society for Computer Simulation, San Diego, pp. 1287-1294.
Isidore, L.J., Back, W.E., 2002, "Multiple Simulation Analysis for Probabilistic Cost and Schedule Integration" , Journal Construction Engineering Management, Vol. 128, No. 3, 211-219.
Palisade Corporation, 2001, Guide to Using @Risk, New York.
Rosenblatt, M., 1952, "Remarks on a Multivariate Transformation" , Annals of Math. Stat., Vol. 23, No. 3, 470-472.
Sakka, Z.I., El-Sayegh, S.M., 2007, "Float Consumption Impact on Cost and Schedule in the Construction Industry" , Journal Construction Engineering Management, Vol. 133, No.2, 124-130.
Zhong, D.H., Zhang, J.S., 2003, "New Method for Calculating Path Float in Program Evaluation and Review Technique (PERT)", Journal Construction Engineering Management, Vol. 129, No. 5, 501-506.
