1 Unit V: Introduction to PERT/CPM Introduction to Project Management: Project: “an organized undertaking” Master of Engineering Thesis Project Finding a job Building a porch Buying a house Design and manufacture a car (Large Program) Put a man on the moon (Huge Program) Definition A project is composed of jobs, tasks or functions and activities that are related to each other. Every project project has one specific specific purpose purpose and required resources resources like like men, money money,, mate materi rial als, s, machi machine nery ry,, minut minutes es,, etc. etc. To plan plan,, impl implem emen ent, t, and and contr control ol the the management management of large, one time projects. projects. Applicable Applicable in Construction Construction,, Shipbuilding, Shipbuilding, Weapons Systems Development, etc. –Applies to uncertain technology projects –Applies to variable cost resource allocation Project Characteristics Single unit o o Many related activities o Difficult production planning & inventory control o General purpose equipment o High labor skills Examples of Projects Building construction o o New product introduction Training seminar o Research project, etc. o Objective of a project: The project should complete within elapsed time o It should use optimum resources without delay o It should complete with a minimum of capital investment. o Project Management: Project Management is the application of knowledge, skills, tools and techniques to project activities in order to meet project requirements.
Project Management: - a discipline "Art and Science". is an art o o is a science and has a set of tools and methods Qualities of Project Manager: Effective Project Manager should have the following qualities:
2 Lead by example Visionaries o Technically competent o Decisive o Good communicators o o Good motivators o Stand up to execs when necessary o Support team members o Encourage new ideas Alternate view of Effective Project Managers : o Leaders (also managers, administrators) o Level headed o Communicators o Goal oriented o Problem solvers (prioritization) o Innovators Work well under pressure (able to laugh) o Technically competent, respected, aware o Know company & its business o o
Project Management Objective To achieve the project goal g oal effectively and efficiently o o To keep customers happy o To keep the team focus on the goal o To make sure that team members work well o To share workload everyone equally Project Management involves the following three phases: 1. Proj Projec ectt Pla Plann nnin ing g project organizing 2. Sched heduling 3. Cont Contrroll olling
1) Proj Project ect Plann Plannin ing: g: - Pro Proje ject ct plan plan is is a map map and and a gui guide de and benc benchm hmar ark k to to measure progress. Establishing objectives o Defining project o Creating work breakdown structure (WBS) o Determining resources o Forming organization o Project Organization Often temporary structure o Uses specialists from entire company o Headed by project manager o
3 –Coordinates activities o –Monitors schedule & costs Permanent structure called ‘matrix organization’ o
o
2) o o o o o
3)
Project Sc Scheduling Sequencing activities Identifying precedence relationships Determining activity times & costs Estimating material & worker requirements Determining critical activities Project Controlling Project Goal Setting |
--What do we want to achieve?
V
Performance Measure |
-- What is happening?
V
Performance Test |
-- Why is it happening?
V
Corrective Action
-- What should be done?
Project Management Techniques: I. Gantt ntt chart II. II. Netw Networ ork k Tech Techni niqu ques es • Critical Path Method (CPM) • Program Evaluation & Review Technique (PERT) I) Gantt chart: Henry Laurence Gantt Henry Laurence Laurence Gantt (1861-1919) (1861-1919) was a mechanical mechanical engineer and management management consultant consultant who is most famous for developing developing the Gantt chart in the 1910s. These Gantt charts were employed on major infrastructure projects including the Hoover Dam and Interstate highway system. Henry Laurence Gantt's legacy to management is the Gantt chart. Accepted as a common commonplac placee projec projectt manage management ment tool tool today, today, it was an innova innovatio tion n of worldworld-wid widee importance in the 1920s. But the Chart was not Gantt's only legacy; he was also a forerunner of the Human Relations School of management and an early spokesman for the social responsibility of business. Life and carrier Henry L Gantt was born into a family of prosperous farmers in Maryland in 1861. His early years, however, were marked by some deprivation as the Civil War brought
4 about changes to the family fortunes. He graduated from Johns Hopkins College and was a teache teacherr before before becoming becoming a draught draughtsma sman n in 1884 and qualif qualifyin ying g as a mechan mechanica icall engineer. From 1887 to 1893 he worked at the Midvale Steel Company in Philadelphia, where he became Assistant to the Chief Engineer (FW Taylor) and then Superintendent of the Casting Department. Gantt and Taylor worked well in their early years years together. Gantt chart During the era of scientific management, Henry L. Gantt developed a tool for displaying the progression of a project in the form of a specialized chart. An early application was the tracking of the progress of ship building projects. Today, Gantt's scheduling tool takes the form of a horizontal bar graph and is known as a Gantt chart, a basic sample of which is shown below: Gantt chart Format Exemplary Gantt chart for building a house:
Dura Durati tion on 1 activity 2 activity 3 activity
: Jan. Jan. Feb. Feb. Mar. ar. Apr Apr.. May May.. Jun Jun.. Jul Jul..
The horizontal axis of the Gantt chart is a time scale, expressed either in absolute time or in relative time referenced to the beginning of the project. The time resolution depends on the project - the time unit typically is in weeks or months. Rows of bars in the chart show the beginning and ending dates of the individual tasks in the project. In the above example, each task is shown to begin when the task above it completes. However, the bars may overlap in cases where a task can begin before the completion of another, and there may be several tasks performed in parallel. For such cases, the Gantt chart is quite useful for communicating the timing of the various tasks. For larger projects, the tasks can be broken into subtasks having their own Gantt charts to maintain readability.
5 Gantt chart Enhancements This basic version of the Gantt chart often o ften is enhanced to communicate more information. o A vertical marker can used to mark the present point in time. o The progression of each activity may be shown by shading or hatched lines in the bar as progress is made, allowing allowing the status of each activity to be known with with just a glance. Dependencies can be depicted using link lines or color codes. o Resource allocation can be specified for each task. o Milestones can be shown. o Gantt chart Role in Project Planning For larger projects, a work breakdown structure would be developed to identify the tasks before constructing a Gantt chart. For smaller projects, the Gantt chart itself may used to identify the tasks. The strength of the Gantt chart is its ability to display the status of each activity at a glance. glance. While While often often generat generated ed using using projec projectt manage management ment software software,, it is easy easy to construct using a spreadsheet, and often appears in simple ASCII formatting in e-mails among managers. For sequencing and critical path analysis, network models such as CPM or PERT are more powerful powerful for dealing with dependencie dependenciess and project completion completion time. Even when network models are used, the Gantt chart often often is used as a reporting tool. Editorial note: The name of this tool frequentl frequently y is misspelled misspelled as "Gannt" or “Gant”. “Gant”. The correct correct spelling is "Gantt." II) Network Techniques: Network Techniques help in designing, planning, organizing, coordinating, controlling and in decision making in order to complete the project economically in minimum available time and limited available resources. More popular Techniques of Network are: C PM Critical Path Method PERT Programme Evaluation and Review Method LCS Least Cost Method RAMS Resource Allocation and Multi-project Scheduling MAP Manpower Allocation Pr Procedure RPSM Resource Pl Planning an and Sc Scheduling Me Method GERT Graphical Ev Evaluation an and Re Review Te Technique Characteristics of network diagram: Advantages of network analysis: Limitations of network analysis: Objectives of network analysis:
6 Features of network Techniques: Logical base for project planning o Simple in nature (straight forward in concept) o Improves coordination and communication o Highlights Trouble spots and pinpoints responsibilities of a project manager o Wider in application o Anticipates unforeseen changes in futures o Used in Construction, Shipbuilding, Weapons Systems Development, etc. o Applies to uncertain technology projects o Applies to variable cost resource allocation o Applications of network analysis: Network Diagram Representation in arrow diagram and CPM / PERT: Network representations of a project, certain basic terms and their definitions are used: 1) Activity : – any individual operation, which utilizes resources and time, and has an end and a beginning. An arrow is commonly commonly used to represent represent an activity activity with with its head indicating indicating the direction direction of progress in the project. project. These are usually usually classifie classified d into following four categories:
Predecessor activity : - activities that must be completed immediately prior to the start of another activity. Successor Successor activity: - activities that cannot be started until one of more of other activities are completed, but immediately succeed them. activities which which can be accomplis accomplished hed concurrently concurrently.. It Concurrent activity : - activities may be noted that an activity can be a predecessor or a successor to an event or it may be concurrent with one or o r more of the other activities. Dummy activity : - it is an imaginary activity which does not consume any kind of resource but merely merely depicts the technological technological dependence. It is represented represented as broken broken arrow. Dummy activity activity is inserted inserted in the network network to clarify the activity activity pattern in the following situations: a) To make activities with common starting and finishing point distinguishable b) To maintain unique number system for different activities c) To keep the logical sequence of activities and their inter relationship d) To identify and maintain the proper precedence relationship between activities
Dummy activities are used in the following situations: Fig. (A) Represents: If p and q activi activitie tiess are concurr concurrent ent and Activi Activity ty r is successor of activity q. Fig. Fig. (B) (B) Repre Represe sent nts: s: If acti activi viti ties es a and e are concurrent; Activity b is after a and e, and activity f is after activity e. Jobs l and m in a certain project must precede the job n. On the the other other hand, hand, the the job o is preceded by the job m only. Fig. (C1) (C1) shows the incorrect incorrect way since, though the
7 relationship between l , m and n are correct, the diagram implies that the job must be preceded by both the jobs l and m. The correct correct representa representation tion using using the dummy dummy d is shown Fig. (C2) obvious that indicated precedence relationships are justified. 2) Event: – An even represents a point in time signifying the completion of some activities and the beginning of new ones. Except starting and finishing finishing event, remaining all events are dual role events in the network. This is usually represented by circle ‘O’ or any geometrical symbol in a network which which also called node or connector. Event can be further classified into following three categories such as… Merge event: - when more than one activity comes and joins at an event. Burst event : - when more than one activity leaves from an event. Merge and burst event : - an activity may be merge and burst at the same time from an event. 3) Sequencing: – the first prerequisite in the development of a network is to maintain the precedence precedence relationship relationship.. In order to make a network, following following points should should be taken into consideration: What job or jobs precede it? What job or jobs follow it? What job or jobs could run concurrently? What controls the start and finish of a job? It is necessary necessary that a network network be drawn with full care. There are many ways ways to draw a network. It is generally agreed that dummy activities be used as liberally as needed in the first attempt, while revising the same network, every attempt should be made to minimize them.
Some of the activities and their relations are given from the following examples: a) Sequential activities: - Activity B can not start before activity A is completed or activity B follows activity A or activity A precedes activity B. Diverging activities: - Activity Q and R can not start before the completion of b) activity P. Activity Q and R could be start at same time. time. c) Converging activities: - Activity N can not start before completion of activity L and M, and these are the predecessor of activity N. d) Mixed activities : - Activity L and M must be completed before start of activity Q and R. These are the successor successor activities of L and M and they are concurrent could start at the same time. Parallel activities activities : - In this activity chains B follows A and F follows E but both e) Parallel activity chains are completely independent of each other. Graphical Representation of Events and Activities: Flow Charting - Uses Nodes and Arrows based on either in the method “Activity o On Node” (AON) or “Activity “Activity On Arrow” (AOA). Most of the practitioners practitioners used method is AOA. o Arrows An arrow leads from tail to head directionally. o o Nodes
8
o
A node is represented by a circle.
Activity On Node o Task is represented by Node as the Completion of an Activity. o Arrows Represent the Sequential Linkages between Activities o For Example, Node 1 is Begin, Node 2 is Complete Task 1, and Node 3 is Complete Task 2. Example: Activity On Arrow o Task is represented by an Arrow Bounded on Either End by a No de (Event) o Each Event is identified by a Number o The Activity is designated by the Leading Even t Number and the Following Event Number - i.e. Activity 1 - 2 Example: 1 2 Rules for drawing network diagram are summarized as follows: 1) Each activity is represented by one and only one arrow in the network.
2) No two activities can be identified by the same end event
For example example activity activity Z and Y (Fig. (Fig. A) have the the same end events. events. The procedure procedure is to introduce a dummy activity either between Z and one of end events or between Y and of the the end end even events ts.. Modif Modifie ied d repr repres esent entat atio ions ns afte afterr intr introd oduc ucin ing g dumm dummy y d are are shown Fig. B. as a result of using the dummy activity d, activities 1 2 Z and Y can now be identified identified by unique end events. events. It must be noted noted that that a dummy dummy activi activitie tiess does does not consum consumee any time time or resour resources ces.. 3) In order to ensure the correct precedence relationship in the arrow diagram, follow following ing questi questions ons must must be checked checked wheneve wheneverr any activity activity is added added to the network.... • What What acti activi vity ty must must be comp comple lete ted d imm immed edia iate tely ly befo before re this this acti activi vity ty can can start? • What act activities must follow this his activit vity? • What What acti activi viti ties es must must occu occurr simu simult ltan aneo eous usly ly with with this this acti activi vity ty?? Few important suggestions for drawing network: 1) Try to avoid arrows which cross each other. 2) Use straight arrows. 3) Do not attempt to represent duration of a activity by its arrow length. 4) Use arrow from left to right or right to left avoid missing two direction, vertical and standing arrows my be used if necessary.
9 5) Use Use dummi dummies es freel freely y in roug rough h draf draftt but but final final netw networ ork k shoul should d not not have have any any redundant dummies. 6) The net work has only one entry point or start event and one point of emergence – called the end event. Common errors in drawing network: Three types of errors commonly observed they are… 1) Dangling Dangling: - to disconnect disconnect and and activity activity before before the complet completion ion of all activities activities in in a network network diagram diagram is known known as dangling dangling error. error. This is is shown in in the followin following g diagram. Here Dangling activity is 2 – 5. 2) Looping Looping or Cycling Cycling: - drawing drawing an endless endless loop loop in a network network is is known as as looping looping error as shown in the following figure. 3) Redunda Redundancy ncy: - unneces unnecessar sarily ily insert inserting ing the dummy activi activity ty in network network logic logic is known as error of redundancy. Shown, in the diagram activity 2 – 4. Labeling the events or node by Dr. Fulkerson’s Rules: A standard procedure called I – J rules developed by Dr. D R Fulkerson: - They are… I. A start start event is the the one which has arrow arrowss emergin emerging g from it but none none entering entering it. it. Find the start event and number it as one II. Delete Delete all all arrows arrows emergi emerging ng from from all number numbered ed events. events. This This will will create create at least least one new start event out of preceding events. III. III. Number Number all new new start start events events 2, 3, 4, … and so on (no defini definite te rule is necess necessary ary,, but numbering from ‘top to bottom’ may facilitate other users in reading the network when there are more than one new start events). IV. Go on repeati repeating ng steps steps number number 2 and and 3 until until the the end is is reached. reached.
Now consider the following network diagram for labeling by Fulkerson’s rule. To number the nodes using Fulkerson’s rule, numbering of nodes 1 and 2 is obvious. Apply step II. The bottom node is the only node from jobs which is emerging out but none none entering entering it. This is is number 3. 3. Applying Applying step step II again, again, node number number 4 is easily obtained and likewise 5 can also be determined. Using step II again, there are two starting points, and either one of them could be numbered 6. Keeping in view the case of numbers 4, 5 and 6 all in a row, the top node is numbered 6. Rest of the numbering procedure is simple simple and the complete network with numbers is shown in the following figure. Numbering the events by DR. Fulkerson’s rules: 1) There There is is a singl singlee initia initiall event event in in the net work work diagra diagram. m. This This initi initial al event event will will have arrows coming out of it it and none entering it. Number this initial event as 1. 2) Neglect Neglect all all the the arrows arrows emerging emerging out out of of the the initi initial al event event numbere numbered d 1. Doing so, it will apparently provide one or more new initial events. Etly prod 3) Number Number thes thesee apparen apparently produce uced dG new init initial ial event eventss as 2, 3, 4 … etc. etc. 4) Again neglect neglect all all emergin emerging g arrows arrows from these numbered numbered events. events. This will create create H few more B initial evens. 5) Follow rule – 3. F J K A
d C
I D
10 6)
Contin Continue ue this this operati operation on until until the last last event, event, which which has no emerg emerging ing arrows arrows,, is numbered. The importance of good numbering procedure can hardly be claimed in a simple network, but the Fulkerson’s procedure has cetin distinct advantages when network is large. First, the Fulkerson’s producer will always detect a close loop in the network if • there is any. In network methods, a close loop loop represents an impossible event. •
Second, numbers are smaller toward the start side and become larger on the end.
•
Third Third advant advantage age will will become become appare apparent nt when a matrix matrix repres represent entati ation on of the network is brought for computerization.