4.26 Elementary Method "Network Planning Technique" (NPT)

#### 1 Identification/Definition of the Method

/Berg, 1973/ Netzplantechnik - Grundlagen - Methoden - Praxis
pp. 15-40: Introduction; pp. 41-62: Network Planning Model

The following delimitation of the definition by /Berg, 1973/ Netzplantechnik - Grundlagen - Methoden - Praxis
must be realized for the V-Model application: the steps information collection and work breakdown structure planning of the structural analysis have already been completed and must therefore no longer be realized within the scope of the NPT.

#### 2 Brief Characteristic of the Method

Objective and Purpose

The Network Planning Technique (NPT) is a method based on the graph theory to analyze, describe, structure, plan, control and steer projects and processes, whereby time, cost, resources, and other influential factors can be taken into consideration.

Means of Representation

Arrows (directed edges) and circles or rectangles (nodes) are the means of representation in a network plan (directed graph). They are used to represent events, activities, and precedence relations.

NPT variants with regard to the representation:

• Activity Node Network Plan (Vorgangsknoten-Netzplan; VKN)
Activities are represented by nodes, the arrows refer to precedence relations (e. g. Metra Potential Method (MPM))
• Activity Arrow Network Plan (Vorgangspfeil-Netzplan; VPN)
Activities are represented by arrows, the logical sequence is represented by the order of the nodes (begin/end of the activities) (e. g. Critical Path Method (CPM))
• Event Node Network Plan (Ereignisknoten-Netzplan; EKN)
Activities are not represented but only events (states) and its chronological dependences (e. g. Program Evaluation and Review Technique (PERT))

Operational Sequence

When applying NPT, structure and time considerations are consequently separated from each other. In structural analysis (1st step) the essential activities are specified and its logical relations are graphically represented. In time analysis (2nd step) the duration of the individual activities is specified (generally estimated) and both the earliest and latest possible start and end times, the critical path, and the float times are calculated on this basis. In the extensive application of the NPT it is then possible to generate a cost and resource analysis.

NPT variants with regard to the determination:

• Deterministic network plan
Both the activity duration and the structure are considered as determinable, with certainty.
• Stochastic network plan
• Time-stochastic network plan
The activity duration cannot be uniquely specified, it is handled as an independent random variable that is subject to a ß-distribution. In PERT three values are listed: optimistic, pessimistic, and probable estimated duration of each activity.
• Structure-stochastic network plan
The structure of the network plan cannot be uniquely specified. The PERT network plan is evaluated with the help of decision nodes (there are 6 types of nodes: input side: and, or, exclusive-or; output side: deterministic, stochastic).
The trend tends more and more into the direction of VKN, contrary to the VPN which dominated in the past.

#### 3 Limits of the Methods Application

The support of a corresponding tools must basically be requested in order to apply the NPT in a project. Manual handling is not advisable. Based on the great effort required for the generation and the update, the application of network plans is only practicable if very complicated precedence relations and logical dependences have to be realized. In most cases it is sufficient to apply method BAR - Bar Plan.

#### 4 Specification of the Methods Allocation

No. Activity Description
4.1 PM1.5
Generation of Preliminary Plan
The main activities listed in the project-specific V-Model and in the functional units listed in the product structure plan must be allocated to each other. Therefore, the activity list thus generated contains definite object-related activity identifications. Since the product structure plan in PM1.5 - Generation of Preliminary Plan is still far from being completed the object information ends mostly with an SW/HW Unit. SW Components or SW modules can be listed in the course of the detailed planning.

The predecessor and successor relations have to be documented in that list for each activity. This information can then be used to set up a first version of the network plan (information about the logical dependences, no information about time). NPT in PM1.5 - Generation of Preliminary Plan is applied in the sense of a preliminary structural analysis.

Subproduct Project Plan.Process Organization is covered by the NPT in PM1.5 - Generation of Preliminary Plan (i. e. from the aspect of a preliminary plan).

4.2 PM4
Detailed Planning
1. Structural Analysis in Activity PM4 - Detailed Planning

The activity list generated in PM1.5 - Generation of Preliminary Plan must be further detailed for the main activity to be initialized. The subactivities have to be listed, together with its related objects.

Analogous to PM1.5 - Generation of Preliminary Plan, the predecessor and successor relations of the instantiated subactivities must also be documented in a network plan.

The subproduct Project Plan.Process Organization is covered by the NPT in PM4 - Detailed Planning (i. e. from the aspect of a detailed plan).

2. Time Analysis in PM4 - Detailed Planning

The guiding values applying for the time analysis are the project start date and the available actual values for the forward calculation, the project completion date, and the provisional delivery deadlines for the backward calculation.

The earliest expected and latest allowable start and termination dates are specified for the activities of the network plan with the help of the two calculation types and on the basis of the effort estimation values.

Subproduct Project Plan.Planned Values is covered by the NPT, together with EMOD - Estimation Models.

4.3 PM7
Risk Management
After the determination of the critical path, i. e. the sequence of work packages without float times, follows the search for and the analysis of possibilities to improve the situation in the risk management. The network plan is recalculated with sensible alternatives and the critical path is checked once more with regard to its risks.

It is also attempted in the risk management (supported by mathematical optimization models of the Operations Research (OR)) to achieve a constant personnel and resource loading over the course of the project or to reduce the project duration.

The results of the path analysis and the optimization are recorded in the report documents; therefore it is not possible to refer to a coverage of the products. The activity Risk Management is covered by the two methods FMEA - Failure Mode Effect Analysis and NPT. In this connection, FMEA is used to detect risks, NPT is used to calculate risks.

4.4 PM8
Project Control
Within the scope of "Project Control" method NPT is applied for a comparison of planned and actual efforts and deadlines after having completed a subactivity.

The result is recorded in the report documents. Therefore it is not possible to refer to a coverage of the product. Activity PM8 - Project Control is generally covered by the additional application of methods EVT - Earned Value Method and NPT which-from various aspects-make it possible to obtain information about the planned actual state. In this connection NPT represents a comparison of the actual state of the project and the planned efforts and deadlines.

4.5 SD2.6
Specification of System Integration
For applying NPT within the scope of the SD activities "Specification of System Integration" or "Specification of SW Integration" it is necessary to generate a structural and time analysis (compare the above items 4.1 and 4.2). Subproduct Integration Plan.Integration Network Plan is covered by the NPT.
4.6 QA1.2
Generation the Assessment Plan
In this case, the application of NPT comprises a structural and time analysis (compare the above listed items 4.1 and 4.2); therefore the complete coverage of subproduct Assessment Plan.Time Schedule is guaranteed.

#### 5 Interfaces

No. Interface Observation Information in Annex 1
5.1 NPT-BAR The results generated for the activity list within the scope of the structural analysis of the NPT are used as the basis for a bar chart.

When converting the bar chart into a framework for the network plan, the content and subject of the work packages, the effort and duration as well as the begin and the end deadlines, the allocation of the work packages to the projects, personnel, etc. will be used.

When converting the network plan into a bar chart, the content and subject of the work packages, the effort and duration as well as the begin and the end deadlines of the work packages will be used.

4.2 Interface BAR-NPT

#### 6 Literature

/Berg, 1973/ Netzplantechnik - Grundlagen - Methoden - Praxis
/DIN 69900.1, 1987/ DIN 69900 Teil 1: Netzplantechnik Begriffe
/DIN 69900.2, 1987/ DIN 69900 Teil 2: Netzplantechnik Darstellungstechnik
/Gewald, 1972/ Netzplantechnik - Methoden zur Planung und Überwachung von Projekten, Band 2: Kapazitätsoptimierung
/Gewald, 1974/ Netzplantechnik - Methoden zur Planung und Überwachung von Projekten, Band 3: Kosten- und Finanzplanung
/Thumb, 1975/ Grundlagen und Praxis der Netzplantechnik, Band 1 und 2
/Voigt, 71/ Fünf Wege der Netzplantechnik
/Wille, 1972/ Netzplantechnik - Methoden zur Planung und Überwachung von Projekten

#### 7 Functional Tool Requirements

SPM04 - Supporting Planning of the Project Realization

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