# Building a Cordless Vacuum Cleaner

Topics: Project management, Critical path method, Resource allocation Pages: 5 (1537 words) Published: June 11, 2011
The Bestclean is a new cordless vacuum cleaner. An analysis of the task of building the Bestclean reveals the following list of relevant activities, their immediate predecessors, and their duration. JobDescriptionImmediate PredecessorsNormal Time(Weeks)

AProduct Design6
BMarket research Plan2
CManufacturing and engineering A3
DPrototypeA5
EMarketing BrochureA3
FCost EstimateC2
GTestingD3
HMarket surveyB,E4
IPricing and forecastH2
JFinal reportF,G,I2

Using the mentioned case:
1. Draw a Gantt chart for the project mentioned above.
2. Calculate the number of week required to complete the project. (a)Draw the network as an activity-on-node network
(b)Fully analyze the network
(c)State (i) the critical path activities; (ii) project duration; (iii) floats of the non-critical activities (d)Construct an early-start Gantt chart and resource profile for the project Please note that you need to justify your answers.

1)Using the list of activities, its duration and predecessors from the case study a Gantt chart for the proposed sequence of activities is drawn below, showing also the late start, for the activities beyond the Critical Path (assuming that all relationships among the activities and its predecessors are End-to-Start)

Figure 1 - Gantt chart for the project
2) The number of weeks to complete the project is the sum of the duration of the activities in the Critical Path, which is: A – E – H – I – J  6 + 3 + 4 + 2 + 2 = 17 weeks. a) We can draw the AON network, as below, with the critical path activities highlighted in red.

Figure 2 - Network Diagram (AON) for the project (Early and Late dates shown) b) As no lag has been mention, the analysis for the above network is shown below, with emphasis to the activities in the Critical Path.

WBSTask NamePredecessorsDuration (weeks)StartFinishFree SlackEarly StartLate StartEarly FinishLate Finish AProduct Design61601666
BMarket Research Plan 21271829
CManufacturing & Engineering A3794 711913
DPrototype A57111 781112
EMarketing Brochure A37907979
FCost Estimate C21011410141115
GTesting D31214112131415
HMarket survey B,E41013010131013
IPricing and forecast H21415014151415
JFinal report F,G,I21617016171617

c)
i) The critical path activities are those whose float is zero, i.e., cannot be delayed without delaying the whole project. In this example the Critical Path activities are: A – E – H – I – J. ii) Project duration is the sum of the Critical Path activities’ duration: 17 weeks.

iii) The activities that have floats are highlighted in the table above – Market research Plan, 7 weeks; Manufacturing & Engineering , 4weeks; Prototype , 1week; Cost Estimate , 4 weeks; Testing , 1 week.

d) In an early-start Gantt chart, the bar of each activity starts at the activity earliest start time and finishes at the earliest finish time.

Figure 3- Early-start Gantt chart for the project

The resource profile for a project or activity describes the utilization of such resource (men, machinery, materials, cash, etc.) throughout the whole duration of the project. The desired profile for most resources would be a constant utilization of the resources against time, and while it not always possible to achieve such ideal profile the project manager should work with that target in mind. While in real life there might be peaks and valley in the resource profiles along the project this is highly undesired, as it denotes the need to deallocate resources which may be difficult to allocate in a another project for the duration of the engagement gap, or it would imply in having different resources, within the same specialty, working at the same project, potentially causing communication and other continuity issues. Usually when analyzing networks to calculate the minimum overall project...