CPM yazılımlarının mukayesesi ve örnek bir CPM yazılımı

Abstract

Bu çalışmada, yabancı kaynakla mevcut CPU yaza lamlar anan mukayesesi yapılmış ve inşaat sektörüne hizmet edebilecek, resmi kuruluşların özellikle Bayandır lık Bakanlığı'nın kullanılmasını şart koştuğu notasyonları ve sınıflamaları kullanarak bir proje yönetimi yazılımı oluşturulmak istenmiş tir. Geliştirilen yazılaman, mevcut yazılımlarla mukayesesi de yapılmıştır. Şebeke çözümlenmesinde öncelik diyagramları CPD diagrams) yöntemi kullanılmıştır ve minimum bellek ile olabildiğince fazla sayada faaliyetten oluşan şebeke çözümü yapılmak istenmiştir.

The activity-on-node CAoN> system so far described sets out essentially only one relationship between activities the start of an activity depends upon the starts of its predecessors. In the 1960s, IBM developed the 'System 360 Project Control System*, which used multiple dependencies and for this the name "precedence network* or 'precedence diagram* was used. This was an unhappy terminology in the sense that several years earlier the name 'precedence diagram' was given to the diagram setting out the necessary precedence relationships in a production flow line. However, the name is now blessed by the BSI and is widely used in AoN literature, and accordingly it is used here. There are four dependencies that can be described Finish- to-star t tor normal) A N ot B Activity B may not start until at least a days after the finish of activity A. The N is the most common coding applied to this arrow and indicates the relationship. It is entered into the input data in a computer system. If activity B may follow immediately upon activity A, then the ot becomes 0 and is either so written or it is ignored. VI Start-to-start S /3 Here, at least ft days must elapse between the start of activity B and the start of activity A. The situation /5>0 then the start of activity B lags behind the start of activity A-is sometimes called a 'lag-start* rela tionship. Again the S represents a common coding, and again if ft=0 it is either so written or ignored. Finish- to- finish F y A 1 B Here, at least y days must elapse between the complention of activity A and the completion of activity B. When y>0 the relationship is said to be a * lag-f,inish* relationship. The usual coding is F, and a zero lag is either written 0 or ignored. 4. Parallel A P & B Activity B may start S days after the start of activity A but it may not finish after the finish of activity A. vıı The lag-start and lag-finish dependencies may be com bined : S ft f r Here, activity B may not start until ft days after the start of activity A, and cannot finish until j- days after the finish of activity A. Critical path evaluation The critical path or the duration of a project is deter mined bay calculating the longest path through the network. This path is determined by going through the following stages : 1> Calculating the forward pass. 2> Calculating the backward pass. 3} Calculating the activity float and determining the critical path of the project. Forward pass a) Terminology : FORWARD PASS - Calculation of early start and early finish dates. EARLY START - Earliest time an activity can logically start. EARLY FINISH Earliest time an activity can logically finish. TARGET START - Imposed start by planning engineering and vm means that the activity to which the date applies will not start BEFORE the time shown, but may start at a later date if the logic so dictates. fcO Time analysis : When drawing networks» time should always flow from left to right. It should also be remembered that when working in days, the day begins one minute past midnight and ends at midnight. Therefore, subsequent activities always start the day after completion of the preceding activity. Backward pass a> Terminology.- BACKWARD PASS Calculates latest start and finish times for activities and constraints. LATEST FINISH - The EARLIEST late start date of any succeeding constraint leading from the activity. LATEST START TARGET COMPETE - Latest finish less activity duration. - An imposed completion date - used to increase the critlcality of an activity. b> Time analysis : The backward pass calculation STARTS AT THE END AND WORKS TOWARD THE FRONT. The calculation process, therefore, starts from the final activity of the network. This should also be the last activity of the forward pass, and is the activity that determines the project duration. Float calculations and the critical path a> Float terminology : TOTAL FLOAT - The amount an activity can be delayed IX. without impacting the end date or intermediate target date of a project. FLOAT CAL - Total float = Late start less Early start CRITICAL PATH - The path through a project with zero float. Any activity delayed on this path will automatically impact the project end date. Resources RESOURCE - Any element exerting a limitation on an activity. RESOURCE SCHEDULE - Plan that is limited by available resources. SCHEDULE DELAY - The amount an activity is delayed through resource limitations. RESOURCE PROFILE - The quantity of resources available for scheduling. ACTIVITY PROFILE - The number of resources required to complete an activity. CALENDER - Details activity resource rest periods and holidays. Summary of precedence network development The following is a recap of the sequence of events in developing a project schedule : 13 Develop list of activities 2> Determine network logic 3> Determine activity durations 4> Allocate activity resources 5) Network time analysis 63 Verify network logic and critical path 75 Resource level schedule In this study, comparison of the existing foreign originated CPM software has been made and aimed at producing a project management software capable of serving for construction sector using notations and classifications stipulated by official institutions and The Ministry of Public Works. The improved software has been also compared to the existing programmes. PD diagrams have been used in network analysis and intended to constitute a network- solution which consists of activities as much as possible by using mini mum memor y.