Free Webinar: Quality Assurance and Refinement for BIM Models

What: Quality Assurance and Refinement for BIM Models
When:Friday, December 16th at 12 Noon Eastern Time
Where: A free online webinar
Duration: 2 hours
How: Register here https://www1.gotomeeting.com/register/395898529

Free webinar: Factory Layout Optimization with FactoryFLOW

Free webinar: Factory Layout Optimization with FactoryFLOW

12/8/2011 11:00 AM - 11:30 AM

Who should attend – Industrial Engineers, Managers
Related Siemens products – FactoryFlow
Features – Material flow diagrams, congestion diagrams, operator walk-paths
Applications – Factory Layout Optimization, Material Flow and Route Utilization Analysis, Material Handling System Validation, Storage Area Planning
Benefits - Reduce non-value added time in factory logistics analysis and optimization, Minimize indirect labor, Improve Communication, Competitive differentiation

Register here

Sequence of Activities: Dependency Determination

Determining the sequence of activities in a project is a necessary step in building a project network diagram. The sequence of activities is the process of identifying the logical relationship between activities. Each activity in a project has at least one predecessor and one successor except for the first and last activities.

Precedence Diagramming Method (PDM) which is also called Activity-On-Node (AON) allows the use of the four types of relationships that are finish-to-start (FS), finish-to-finish (FF), start-to-start (SS), and start-to-finish (SF). Figure 1 shows the representation of these different relationships. So what those relationships stand for?

Finish-to-start (FS): The predecessor activity must finish in order for the successor activity to start. This relationship is the most deployed in project planning. Assume there are two activities, A and B where A is a predecessor of B, then it means “finish activity A to start activity B”. For example, finish placing the reinforcement of column 1 to start pouring concrete in column 1.

Finish-to-finish (FF): The predecessor activity must finish in order for the successor activity to finish. This means “finish activity A to finish activity B”. For example, finish placing the reinforcement of a wall to finish the formwork of that wall.

Start-to-start (SS): The predecessor activity must start in order for the successor activity to start. This means “start activity A to start activity B”. For example, start placing the concrete of a slab to start finishing the concrete of that slab.

Start-to-finish (SF): The predecessor activity must start in order for the successor activity to finish. This relationship is rarely used. This means “start activity A to finish activity B”. For example, start the night shift of security personal to finish the day shift of security personal. In this case, the security personal of the day shift cannot end his shift before the arrival of the security personal of the night shift. If the security personal of the night shift is running late, then the security personal of the day shift will have to wait (i.e. cannot finish his shift).  

Now that the types of relationships are explained, the next question would be “which relationship to use?” To answer this question, project planners should know the how the work will be carried out (i.e. construction method). By understanding the construction method, a project planner can determine the dependency between the activities. PMBOK describe three types of dependencies which are mandatory, discretionary, and external dependencies.

Mandatory dependencies (also referred to as hard logic) are the ones that contractually/legally required or forced by the construction method or nature of work. In construction projects, mandatory dependencies usually involve physical limitations. For example, a contractor cannot pour the concrete before the placing the reinforcement; a contractor cannot construct the bridge deck before finishing the construction of the columns for that span.

Discretionary dependencies (also referred to as soft logic) are the ones that result from a preferred method or best practice of carrying out an activity. It is worth mentioning that this type of dependencies can result in different type of relationships based on the setting of the project. For example, in Design-Build projects the design of a building can be finalized before commencing the construction or the construction can start before the final design is still in progress.

External dependencies are the ones that are forced by non-project activities yet they are necessary for the start of project activities. In some situations, the project team have no control over these dependencies. For example, a contractor cannot start the construction of a building before issuing a construction permit (non-project activity). In this case, the time needed to issue the construction is outside the project team’s control.

Sometimes it is necessary to use lead or lag time between activities to maintain an accurate logic between activities. This will be the topic of a future post.

Please feel free to comment of give a feedback on my post.

Bibliography

Project Management Institute. (2008). A Guide to the Project Management Body of Knowledge (PMBOK). Newtown Sqaure, Pennsylvania: Project Management Institute, Inc.

Project Schedule Network Diagram

The project schedule network diagram is a visual representation of the activities in a project and their inter-dependency. There are two common approaches to build a network diagram. The first approach is the Precedence Diagramming Method (PDM) which is also called Activity-On-Node (AON) (Figure 1).


Figure 1  Precedence Diagramming Method Example

In this network diagram, the activities are represented by boxes (node) and the logical relationships between the activities are presented by arrows. PDM allows the use of the four types of relationships that are finish-to-start (FS), finish-to-finish (FF), start-to-start (SS), and start-to-finish (SF). Figure 2 shows the representation of these different relationships. This approach is the most common one and supported by major scheduling software such as Primavera and MS Project. 


Figure 2 Relationship Representation in PDM

The second type is the Activity-On-Arrow (AOA) as shown in Figure 3. In this network diagram, the activities are represented by an arrow and connected by nodes. The nodes represent an event which could be the start or completion of an activity. Finish-to-start is the only relationship that can be used to express the dependency between activities when using the AOA approach. Sometimes it is necessary to use a dummy activity, which is an activity that has no time, to maintain the logical relationships in an AOA network. 


Figure 3 Activity On Arrow Example

If you have any questions, please do not hesitate to ask.

In future posts I will talk about the logical relationships between activities, how to construct an AOA network, and finding the critical path.

Free PMP Exam Simulation Test !

Free PMP Exam Simulation Test !

200 Questions, 4 hour Test
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Free live Online classes on Project Quality Management.

Timings are provided in GMT. Please convert it to you local timings

Date and Timing :
26th November, 2011 . 1.30 AM GMT - Project Quality Management

URL : http://www.simplilearn.com/simplilearn/webinars

Kindly note that, if you are unable to attend the live webinar on these topics, due to time constraints, you can request for the recorded version of the webinars.

Based on PMBOK 4th Edition

Please write to leisley@simplilearn.com to get access code to join the webinar.

Free live Online classes on Project Risk Management

Timings are provided in GMT. Please convert it to you local timings

Date and Timing :

25th November, 2011 - 10 AM GMT - Project Risk Management

URL : http://www.simplilearn.com/simplilearn/webinars

Kindly note that, if you are unable to attend the live webinar on these topics, due to time constraints, you can request for the recorded version of the webinars.
Based on PMBOK 4th Edition
Please write to leisley@simplilearn.com to get access code to join the webinar.

Disaster Prevention: Preparing for the Worst - Free eBook!

Free eBook to Disaster Prevention: Preparing for the Worst. This backup and recovery guide offers best practice articles to help your system and organization survive.

You can download here

Free Webinar: What You Must Know About Stakeholder Management 7/12/2011

Date/Time: 12/7 11:00 am to 12:00 pm EDT

Course ID: MDW1250 / Duration: 1 Hour / Credits: 1 PDU

Once of the most critical aspects of project management is doing what’s necessary to develop and manage relationships with all individuals that the project impacts. In this webinar, you’ll learn techniques for identifying stakeholders, analyzing their influence on the project, and developing strategies to communicate, set boundaries, and manage competing expectations. By effectively managing your stakeholders, you will be better able to keep a lid on scope creep, ensure project requirements are aligned, understand tolerance for risk, and mitigate issues that would otherwise delay the project. Effective stakeholder management is proof of your influence in an organization, and a key component to a healthy project environment.

Key learning points:

- How to identify project stakeholders
-How to conduct a stakeholder analysis
-How to manage different types of stakeholders

Bonnie Cooper, PMP®, Trainer and Consultant for Corporate Education Group, is a 25-year Information Technology professional and currently the Program Portfolio Director of the Massachusetts Medical Society's Corporate IT PMO. Her portfolio includes The New England Journal of Medicine's manuscript tracking, desktop publishing, advertising management, and corporate ERP systems. In her current role, Ms. Cooper is responsible for coordinating the efforts of project teams, defining a consistent software development methodology, and leading the program to re-engineer the membership services platform. Ms. Cooper is a project management educator, and a published writer of her experiences in facilitating the PMO to drive IT strategy and governance.

To register click here

Free webinar: People Skills For Project Managers December 9, 2011

The webinar will be an introduction to five key people skills for project managers – empathy, communication, anticipation, organization, pragmatism.

The webinar is on December 9, 2011 at 10 am CST. you can register here.

Program Evaluation and Review Technique (PERT) Calculation Steps

The objective of this post is to explain how program evaluation and review technique (PERT) can be used to schedule a project with uncertainty. 

The main difference between CPM and PERT is that PERT uses probabilistic durations instead of deterministic ones. In PERT, each activity has three estimated durations which are optimistic, most likely, and pessimistic. The purpose of using these three different durations is to model the uncertainty inherited in the activity durations.

The steps of scheduling a project using PERT will demonstrated through the following example. The information of the project is presented in Table 1. It should be noted that in this example, the finish to start relationship is used. The same procedure would be followed if different relationships do exist. 

Step 1: Calculate the mean, standard deviation, and variance of each activity using the following equations. The results of this step are presented in Table 2.

Step 2: Construct the precedence diagram and preform CPM analysis using the mean duration as shown in Figure 1. Then find the critical path which in case is B-C-G-H-K-M-O-P-Q-R. Next, calculate the standard deviation of the project which is the square root of the sum of the variances of the critical path activities. In this case it is 3.75.

Figure 1 Precedence Diagram

Step 3: Probability analysis using the calculated information. Two main questions can be answered using probability analysis. The first question is “What is the probability that the project will be finished on or before 98 (you can choose the target duration that you are interested in) days?” To answer this question Z, which is the number of standard deviations the target date lies from the expected date, should be calculated using the NORM.DIST function in Excel 2010 (NORMDIST function in Excel 2007) or the following equation. 

The next step would be finding the area under the normal distribution curve using normal distribution tables that corresponds to a Z value of 0.8. By doing that, we can find that there is 78.81 % chance that project can finish in 98 days or less. It should be noted that if the Z has a negative value, then the probability would be 1 – table value.  

The second question is “What is the due date under which the project has 99 % (you can choose the confidence level that you are interested in) chance of completion?” In this question, we are given the area under the curve which 0.99. We can either find the answer by using NORM.INV function in Excel 2010 (NORMINV function in Excel 2007) or the following steps. What we need to find is the Z value from the normal distribution table. In this case, Z is 2.33.

I have also developed an Excel sheet that you can download from here. 

If you have any questions, please do not hesitate to ask.

Program Evaluation and Review Technique (PERT) Excel Sheet

I have developed an Excel sheet that shows how to preform project scheduling using PERT. You can modify it to accommodate your project. You can download it from  here. To learn more about the steps of generating schedules using PERT click here. It should be noted that in this example, the finish to start relationship is used in this Excel file. The Excel workbook was developed using the 2010 version. If you are using MS Excel 2007, you need to do this small modification. In the Schedule! sheet, the functions in cell J7 and N10 should be changed to NORMDIST and NORMINV respectively.

If you have any questions, please do not hesitate to ask.