The Costs of Crashing—A Comment

1971 ◽  
Vol 35 (4) ◽  
pp. 63-66
Author(s):  
Neil E. Beckwith
Keyword(s):  
Project Duration ◽  
Total Cost ◽  
Total Project

This article presents an algorithm for selecting the activities which should be expedited to minimize the total cost of achieving a particular total project duration. The author comments on “The Costs of Crashing” which appeared in the July, 1970 issue of the JOURNAL OF MARKETING.

Implementation Sequence Optimization for Dedicated Bus Lane Projects

2021 ◽  
pp. 036119812110148
Author(s):  
Murat Bayrak ◽  
S. Ilgin Guler ◽  
Paul Schonfeld
Keyword(s):  
Resource Constraints ◽  
Optimal Schedule ◽  
Transmission Model ◽  
Project Duration ◽  
Total Cost ◽  
Transportation Projects ◽  
Bus Lane ◽  
Upper Level ◽  
Demand Patterns ◽  
Total Project

Transportation projects are often implemented in phases, and the total project duration can span years. Optimization of the sequence in which transportation projects are implemented can decrease the severity of disruptions caused by construction, reduce the total cost of projects, and increase the present value of the benefits of the project. This paper presents a method for optimizing the sequence and location of dedicated bus lane implementations. The proposed method is based on a bi-level optimization framework. The lower level simulates the traffic using a link transmission model to evaluate car and bus delays, while the upper level optimizes the locations of bus lanes and/or the implementation sequence of a given bus lane configuration. If the budget or other resource constraints are binding, the optimized sequence uniquely determines the optimal schedule. The solution method is evaluated for a test network, and an analysis of sensitivity to different demand patterns and different bus lane configurations is conducted. First, the optimized locations for bus lane implementation are determined for an illustrative test network. Results suggest that, when considering the implementation sequence for the optimized set of bus lane locations, the sequence of implementation does not yield significant benefits. However, if bus lanes are implemented on every possible link, the results suggest that prioritizing the implementation of bus lanes on peripheral links would reduce the total cost the most. These locations coincide with the set of optimized locations for bus lane implementation. Further tests considering non-uniform demand patterns also confirm these findings.

scholarly journals Cost Optimal Project Scheduling

Organizacija ◽  
2008 ◽  
Vol 41 (4) ◽  
pp. 153-158
Author(s):  
Uroš Klanšek ◽  
Mirko Pšunder
Keyword(s):  
Nonlinear Programming ◽  
Objective Function ◽  
Project Scheduling ◽  
Programming Approach ◽  
Project Duration ◽  
Numerical Example ◽  
Activity Duration ◽  
The Cost ◽  
Total Project Cost ◽  
Total Project

Cost Optimal Project SchedulingThis paper presents the cost optimal project scheduling. The optimization was performed by the nonlinear programming approach, NLP. The nonlinear total project cost objective function is subjected to the rigorous system of the activity precedence relationship constraints, the activity duration constraints and the project duration constraints. The set of activity precedence relationship constraints was defined to comprise Finish-to-Start, Start-to-Start, Start-to-Finish and Finish-to-Finish precedence relationships between activities. The activity duration constraints determine relationships between minimum, maximum and possible duration of the project activities. The project duration constraints define the maximum feasible project duration. A numerical example is presented at the end of the paper in order to present the applicability of the proposed approach.

scholarly journals Benchmarking Characteristics of Steam Assisted Gravity Drainage (SAGD) Projects: Based On Interview Findings

2015 ◽  
Vol 3 (2) ◽  
pp. 1 ◽  
Author(s):  
Elias Ikpe ◽  
Jatinder Kumar ◽  
George Jergeas
Keyword(s):  
Oil And Gas ◽  
Oil And Gas Industry ◽  
Gravity Drainage ◽  
Gas Industry ◽  
Project Duration ◽  
Steam Assisted Gravity Drainage ◽  
Qualitative Research Methodology ◽  
Definition Of ◽  
Total Project Cost ◽  
Total Project

SAGD is a relatively new method of oil extraction and recovery in Alberta oil and gas industry and the number of new SAGD plants in Alberta is expected to increase within this decade. The paper discusses the interviews finding of benchmarking characteristics of the SAGD projects. The research reviewed and analysed definition of capacity, main features, life cycle/ phases of SAGD projects and also major risks associated with it. A qualitative research methodology was employed in investigating the characteristics of SAGD projects. Interviews were conducted with industry practitioners, which contained open-ended questions. The result found the definition of capacity of SAGD projects is barrels/day and from the lifecycle of SAGD projects procurement/cosntruction phase is 75% of the total project cost while other phase in total constiutues the 25% of the total cost of the project. On the schedule prospective, procurement/construction phase constitute the 55% of the total project duration. This method has the potential to contribute to a reduction in cost and schedule overruns and improves SAGD project performance. It is concluded that the results of the study will help in achieving a higher rate of productivity in the Alberta oil and gas industry.

scholarly journals Designing project schedule using crashing method to compress the fiber to the home project schedule

2021 ◽  
Vol 2 (1) ◽  
pp. 51
Author(s):  
Zha Sha Putri Anugerah ◽  
Devi Pratami ◽  
Mohammad Deni Akbar
Keyword(s):  
Total Duration ◽  
Project Work ◽  
Home Networks ◽  
Project Schedule ◽  
Project Cost ◽  
Total Cost ◽  
Overtime Work ◽  
Fiber To The Home ◽  
Total Project Cost ◽  
Total Project

ABC Company is an agent of network construction, operation, and maintenance. ABC Company is currently implementing the STTF (Shit to the Front) project, which is the project to add FTTH (Fiber to the Home) networks in areas that can have high customer demand. One of the STTF project construction sites is the Indra Prahasta II housing location. However, the project is currently experiencing work delays due to the Covid-19 disaster in Indonesia. Delays in project execution can result in potential prospects choosing another company that provides similar services. The project schedule can be accelerated using the crashing method and TCTO (Time Cost Trade-Off) analysis to solve this problem. This research's acceleration will be carried out with alternatives for adding 3 hours, 2 hours, 1 hour, and an alternative to increasing workers' number. This project has an average duration of 55 working days with a total cost of Rp 604,124,460. The results obtained from data processing, on the alternative of adding 1 hour of overtime work, the total duration becomes 54 working days with total project cost is Rp 605,734,138. In addition to 2 hours of overtime work, the project's total duration can be reduced to 54 days with a total project cost Rp 606,803,619. And for the addition of 3 hours overtime, the total duration can be shortened to 54 days with a total cost of Rp 606,803,619. As for increasing the number of workers, project work duration can be shortened to 54 working days with a total project cost Rp 604,556,748

scholarly journals PERCEPATAN WAKTU PELAKSANAAN PEKERJAAN KONSTRUKSI DENGAN METODE CPM DAN TCTO

2019 ◽  
Vol 11 (1) ◽  
pp. 33-40
Author(s):  
Cut Zukhrina Oktaviani ◽  
Ibnu Abbas Majid ◽  
Risdiawati Risdiawati
Keyword(s):  
Completion Time ◽  
Construction Projects ◽  
Critical Path ◽  
Minimum Cost ◽  
Time Cost ◽  
Trade Off ◽  
Project Duration ◽  
Project Completion ◽  
Project Costs ◽  
Total Project

Construction delays are a common and major concern in most construction projects. Construction project delay can indirectly affect of project performance. Delay resolve method is to schedule crashing with various methods. This crashing planning is done by combining the Critical Path Method (CPM) and Time-Cost Trade-Off (TCTO) method for the minimum cost in crash duration calculation. Project A data is used to be a case studi in crash duration calculation and costs increase. Rescheduling with CPM result project completion time 120 days and after crashing project duration becomes 94 days, there was a reduction 26 days project completion time. Crashing programme are do to 18 activities from 30 critical activies rescheduling with CPM result. Total project costs changes is Rp. 19.923.466,- due working time addition (overtime) to reduce project time with Time Cost Trade Off method. Normal condition project costs is Rp. 985,171,182.52 and after duration crash becomes Rp. 1,005,094,648, -.

IMPACT OF BIDDING ENVIRONMENT ON CHANGE ORDERS

2016 ◽  
Vol 3 (1) ◽  
Author(s):  
Bahadir V. Barbarosoglu ◽  
David Arditi
Keyword(s):  
Construction Projects ◽  
Potential Change ◽  
Project Cost ◽  
Change Orders ◽  
Public Building ◽  
Project Duration ◽  
Project Completion ◽  
The Difference ◽  
Dollar Amount ◽  
Total Project

Change orders occur during construction, and usually increase both construction cost and project duration. This paper investigates how change orders are related to the bidding environment. The data used in this study were collected from 74 public building construction projects awarded by the Public Building Commission of Chicago in the seven-year period 2008-2015. The contract values range between $0.3-$70 million, and the total worth of the projects is a little over $1.1 billion. While delay may result in liquidated damages for contractors, increase in project cost can cause financial problems for owners. It is in the interest of owners and contractors to study similar past projects, and to observe how change orders are affected by the level of competition in bidding. Owners must budget for contingencies, and contractors must adjust their resources in anticipation of change orders. It would therefore be quite desirable for owners and contractors to be able to predict the dollar amount and duration implications of potential change orders by making use of past historical data. The prediction of the dollar amount and duration implications of potential change orders before the construction starts can alert construction owners and contractors to potential delays in total project completion time and potential overruns in total project cost. Knowledge about potential change orders creates a predictable environment and improves the relationship between owners and contractors. The results of this study indicate that contractor-driven change orders are positively related to the difference between the lowest and the second lowest bids.

scholarly journals   Project costs planning in the conditions of uncertainty

2012 ◽  
Vol 58 (No. 2) ◽  
pp. 72-84 ◽  
Author(s):  
H. Štiková
Keyword(s):  
Critical Path ◽  
Project Planning ◽  
Fuzzy Approach ◽  
Project Duration ◽  
Planning And Control ◽  
New Information ◽  
Project Costs ◽  
Project Network ◽  
And Control ◽  
Total Project

The fuzzy approach to the project network analysis of the project planning and control is commonly oriented on the fuzzy critical path setting and the project duration monitoring. In the article, this approach is improved by the addition of the project costs perspective to the standard time aspect. The relations for the fuzzy quantity of the total project costs and for its membership function are derived. The example demonstrates the application of the theoretical relations and shows how the enhanced fuzzy approach can be used when different project variants are to be compared. The example also reveals how the fuzzy approach with the project costs monitoring brings new information for the project planning and management and for the risk management.  

Cost Analysis for Decommissioning of Nuclear Power Plants With Uncertainties

2018 ◽  
Author(s):  
Naoko Watanabe ◽  
Ryohei Miyoshi ◽  
Tamotsu Kozaki ◽  
Shingo Tanaka ◽  
Satoshi Yanagihara
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Radioactive Waste ◽  
Waste Management ◽  
Nuclear Power ◽  
Radioactive Waste Management ◽  
Project Duration ◽  
Total Cost ◽  
Safe Storage ◽  
Low Level

Decommissioning cost including radioactive waste management for 1100 MWe nuclear power plant (BWR) was analyzed comparing multiple scenarios. The total cost of decommissioning nuclear power plant was first estimated including the radioactive waste management cost for the standard Japanese decommissioning case with 30 years of the project duration including approximately 20 years in safe storage. It showed that the cost relating to waste management accounts for more than half of the total cost. Focusing on the radioactive waste management cost, the duration of safe storage was varied as a parameter. The timing of waste disposal was a key parameter determining the waste management cost due to the decay of radioactive nuclides resulting in the decrease in the total volume of the radioactive waste, and the change in the ratio of the waste volume in the three radioactive waste categories (intermediate-level, low-level, and extremely low-level). The total cost showed the minimum value at around 60 years of the project duration balancing the waste management cost and period dependent cost for safe storage.

scholarly journals An Estimation of the Learning Curve Effect on Project Duration with Monte Carlo Simulation

2018 ◽  
Vol 49 (1) ◽  
pp. 66-71 ◽  
Author(s):  
Levente Mályusz ◽  
Anita Varga
Keyword(s):  
Learning Curve ◽  
Learning Effect ◽  
Test Problems ◽  
Activity Time ◽  
Project Duration ◽  
Curve Effect ◽  
Normal Duration ◽  
Minimum Estimate ◽  
Repetitive Activities ◽  
Total Project

The aim of this paper is to estimate learning curve effect on project duration with the mean of project scheduling techniques. To measure this effect only one assumption is taken: the activity time individuals / groups take to perform an activity decreases at a given rate as experience is gained with the activity. Unfortunately this effect directly is not taken into account by project management software. In some software after scheduling, supervisor manually can switch on the "as soon as possible" or "as late as possible" buttons on an activity.Monte Carlo simulation was used to model the risks in the total project durations. It is assumed that the (normal) durations of the activities can vary according to the beta distribution. The minimum estimate is 95 % of the original (normal) duration, and the maximum estimate is 140 % of the original (normal) duration. We assumed that most likely value is the (normal) duration of each activity. The learning effect on project duration with the help of test problems and real problems was investigated. In test problems learning effect can occur between two consecutive activities. These pairs are chosen randomly. After calculating project duration, these pairs are allocated to be closer to each other using the predecessor's total float time. It is assumed that the duration of impending repetitive activities is shorter due to the learning curve effect if the gap between consecutive activities is small enough. This iteration is carried out until it is not possible to shorten the successor's activity time in a pair. It is shown that this effect brings a 2-3 % shorter project duration meanwhile variance is also left in a 1-2 % range. Numerical tests were implemented by XPRESS-Mosel Optimization Software.

Sign in / Sign up

Export Citation Format

Share Document