Project Time Managementإدارة وقت المشروع
مقدمة الفصل
ماذا ستتعلم في هذا الفصل
- What is project time management.
- Understand the importance of project schedules and good project time management.
- Define activities as the basis for developing project schedules.
- Describe how project managers use network diagrams and dependencies to assist in activity sequencing.
- Understand the process of sequencing activities and the four types of activity dependencies.
- Use Gantt chart, critical path method, critical chain scheduling for planning schedule information.
أقسام الفصل
- 1Project time management and its processesإدارة وقت المشروع وعملياتها
- 2Planning schedule management and defining activitiesتخطيط إدارة الجدول وتعريف الأنشطة
- 3Sequencing activities and network diagramsترتيب الأنشطة ومخططات الشبكة
- 4Estimating activity resources and durationsتقدير موارد الأنشطة ومددها
- 5Developing the schedule: Gantt charts, CPM, slack, crashing and fast trackingبناء الجدول: جانت والمسار الحرج والسماحية والضغط والتسريع
- 6Critical chain scheduling and controlling the scheduleجدولة السلسلة الحرجة والتحكم في الجدول
تلميح: استخدم أسهم لوحة المفاتيح للتنقل بين الشرائح.
What is project time management?ما إدارة الوقت؟
Project time management and its processes
| Initiating | Planning | Executing | Monitoring & Control | Closing |
|---|---|---|---|---|
| — | Plan schedule management, define activities, sequence activities, estimate activity resources, estimate activity durations, develop schedule | لا تذكر الشرائح شيئًا هنا. | Control schedule | لا تذكر الشرائح شيئًا هنا. |
- Project time management describes the processes and methods required to create and manage appropriate schedules to complete the project.
- Project time management involves the processes required to ensure timely completion of a project.
Time management processesعمليات إدارة الوقت
Project time management and its processes
| Processالعملية | What it involvesماذا تتضمن | Main outputsأهم المخرجات |
|---|---|---|
| 1. Planning schedule management | Determining the policies, procedures, and documentation that will be used for planning, executing, and controlling the project schedule. | Schedule management plan |
| 2. Defining activities | Identifies the lowest level of work on the WBS, “work packages”, that needs to be performed to create the finished product deliverable. |
|
| 3. Sequencing activities | Identifying and documenting the relationships between project activities. |
|
| 4. Estimating activity resources | Estimating how many resources (people, equipment, materials) a project team should use to perform project activities. |
|
| 5. Estimating activity durations | Estimating the number of work periods that are needed to complete individual activities. |
|
| 6. Developing the schedule | Analyzing activity sequences, resource estimates, and duration estimates to create the project schedule. |
|
| 7. Controlling the schedule | Controlling and managing changes to the project schedule. |
|
Processes 1–6 are in the planning process group; controlling the schedule is in monitoring and controlling.
1. Planning schedule managementتخطيط إدارة الجدول
Planning schedule management and defining activities
Planning how the schedule will be managed throughout the life of the project.
| Componentالمكوّن | Descriptionالوصف |
|---|---|
| Project schedule model development | Contains project activities with estimated durations, dependencies, and other planning information that can be used to produce a project schedule. |
| Level of accuracy and units of measure | Discusses how accurate schedule estimates should be and determines whether time is measured in hours, days, or another unit. |
| Control thresholds | Variance thresholds, such as ±10%, are established for monitoring schedule performance. |
| Rules of performance measurement | For example, if team members are expected to track the percentage of work completed, this section specifies how to determine the percentages. |
| Reporting formats | Describes the format and frequency of schedule reports required for the project. |
| Process descriptions | Describes how all of the schedule management processes will be performed. |
2. Defining activitiesتعريف الأنشطة
Planning schedule management and defining activities
An element of work normally found on the WBS that has an expected duration, cost, and resource requirements.
Activity definition involves developing a more detailed WBS and supporting explanations to understand all the work to be done so you can develop realistic cost and duration estimates.
Inputs:
- Schedule management plan.
- Scope baseline.
- Enterprise environmental factors — relevant government or industry standards, the organization's infrastructure, and marketplace conditions.
- Organizational process assets — formal and informal plans, policies, procedures, guidelines, information systems, financial systems, management systems, lessons learned, and historical information.
A tabulation of activities to be included on a project schedule: the activity name, an activity number, and a brief description.
More schedule-related information about each activity, such as predecessors, successors, logical relationships, resource requirements, constraints, imposed (executed) dates, and assumptions.
A significant event that normally has no duration.
سؤال سريع
Planning schedule management and defining activities
3. Sequencing activitiesترتيب الأنشطة
Sequencing activities and network diagrams
Sequencing activities means determining the dependencies, or relationships between project activities or tasks.
A dependency pertains to the sequencing of activities:
- Does a certain activity have to be finished before another can start?
- Can the project team do several activities in parallel?
- Can some overlap?
تذكّر سبب كل اعتمادية ومثالها.
- 1Mandatory dependencies (hard logic)اعتماديات إلزامية
Inherent in the nature of the work being performed. E.g. you cannot test code until the code is written.
- 2Discretionary dependencies (soft logic)اعتماديات اختيارية
Established based on the knowledge of best practices, even though there are many other possible sequences. E.g. not starting detailed design until the users sign off on all of the analysis work.
- 3External dependenciesاعتماديات خارجية
Involve the relationships between project and non-project activities. E.g. installing a new operating system may depend on delivery of new hardware from an external supplier.
You must determine correct dependencies to create a realistic schedule.
Network diagrams: the arrow diagramming methodمخطط الأسهم (ADM)
Sequencing activities and network diagrams
Network diagrams are the preferred technique to show activity sequencing. Two main formats: Arrow Diagramming Method (ADM) or activity-on-arrow (AOA), and Precedence Diagramming Method (PDM).
ADM consists of:
- Letters that represent activities with dependencies.
- Lines with arrows that represent sequencing or relationships between tasks.
- Nodes or circles which represent the starting and ending points of activities.
ADM can only show finish-to-start dependencies.
Process for creating ADM/AOA diagrams
- 1
Find all of the activities that start at node 1.
- 2
Draw their finish nodes and draw arrows between node 1 and those finish nodes.
- 3
Put the activity letter or name and duration estimate on the associated arrow.
- 4
Continue drawing the network diagram, working from left to right.
- 5
Look for bursts (a single node followed by two or more activities) and merges (two or more nodes precede a single node).
- 6
Continue until all activities that have dependencies are included.
- 7
As a rule of thumb, all arrowheads should face toward the right, and no arrows should cross.
| Activity | From node | To node | Duration |
|---|---|---|---|
| A | 1 | 2 | 1 |
| B | 1 | 3 | 2 |
| C | 1 | 4 | 3 |
| D | 2 | 5 | 4 |
| E | 3 | 5 | 5 |
| F | 3 | 6 | 4 |
| G | 4 | 7 | 6 |
| H | 5 | 6 | 6 |
| I | 7 | 6 | 2 |
| J | 6 | 8 | 3 |
ADM example 1مثال 1 على مخطط الأسهم
Sequencing activities and network diagrams
| Activity | Duration (hours) | Immediate predecessors |
|---|---|---|
| A | 3 | لا تذكر الشرائح شيئًا هنا. |
| B | 4 | لا تذكر الشرائح شيئًا هنا. |
| C | 6 | لا تذكر الشرائح شيئًا هنا. |
| D | 5 | A |
| E | 1 | B |
| F | 6 | B |
| G | 7 | C, D, E |
المسألة
Draw the ADM network diagram.
خطوات الحل
- A(3), B(4) and C(6) start at node 1.
- D follows A; E and F follow B; G follows C, D and E.
النتيجة
Arrows in the slide 27 solution: A(3) 1→2; C(6) 1→4; B(4) 1→3; D(5) 2→4; E(1) 3→4; F(6) 3→5; G(7) 4→5.
Dummy activitiesالأنشطة الوهمية
Sequencing activities and network diagrams
Have no duration and no resources, but are occasionally needed on AOA network diagrams to show logical relationships between activities. They are represented with dashed arrow lines.
| Activity | Duration (hours) | Immediate predecessors |
|---|---|---|
| A | 2 | لا تذكر الشرائح شيئًا هنا. |
| B | 3 | لا تذكر الشرائح شيئًا هنا. |
| C | 5 | لا تذكر الشرائح شيئًا هنا. |
| D | 6 | A, B |
| E | 8 | C |
| F | 2 | C |
| G | 4 | D, E |
Solution arrows: A(2) 1→2; dummy 2→3; B(3) 1→3; C(5) 1→4; D(6) 3→5; E(8) 4→5; F(2) 4→6; G(4) 5→6. Activities A and B both start at the same event and need to end at the same event, since D depends on them both; the dummy activity is introduced to ensure unique numbering.
| Activity | Duration (hours) | Immediate predecessors |
|---|---|---|
| A | 2 | لا تذكر الشرائح شيئًا هنا. |
| B | 4 | لا تذكر الشرائح شيئًا هنا. |
| C | 5 | A, B |
| D | 3 | B |
| E | 6 | C |
| F | 3 | C |
| G | 8 | D |
| H | 2 | D, F |
Solution arrows: A(2) 1→2; B(4) 1→3; dummy 3→2; C(5) 2→4; D(3) 3→5; E(6) 4→7; F(3) 4→6; dummy 5→6; H(2) 6→7; G(8) 5→7. A dummy is needed as C depends on both A and B but D depends on B only; another is needed as G depends on D only but H depends on both F and D.
Precedence diagramming method and dependency typesمخطط الأسبقية وأنواع الاعتماديات
Sequencing activities and network diagrams
PDM consists of:
- Boxes that represent activities.
- Arrows that show relationships between activities.
| Task dependencyالاعتمادية | Descriptionالوصف |
|---|---|
| Finish-to-start (FS) | Task (B) cannot start until task (A) finishes. |
| Start-to-start (SS) | Task (B) cannot start until task (A) starts. |
| Finish-to-finish (FF) | Task (B) cannot finish until task (A) finishes. |
| Start-to-finish (SF) | Task (B) cannot finish until task (A) starts. |
PDM vs. AOAلماذا PDM؟
- Most project management software uses the precedence diagramming method.
- Using PDM avoids the need to use dummy activities.
- PDM shows different dependencies among tasks, whereas AOA network diagrams use only finish-to-start dependencies.
AOAمخطط الأسهم
- Can only show finish-to-start dependencies.
- Occasionally needs dummy activities.
سؤال سريع
Sequencing activities and network diagrams
4. Estimating activity resourcesتقدير موارد الأنشطة
Estimating activity resources and durations
Estimating the type and quantities of material, human resources, equipment, or supplies required to perform each activity.
Important issues in estimating resources:
- How difficult/complex will it be to complete specific activities on this project?
- What is the organization's history in doing similar activities?
- Are the required resources available? Internal or external.
- Very important to match the right person with the right task!
Main outputs:
- List of activity resource requirements.
- Project document updates.
- A resource breakdown structure.
A hierarchical structure that identifies the project's resources by category and type — e.g. categories: analysts, programmers, testers; programmer types: COBOL programmers, Java programmers.
5. Estimating activity durationsتقدير مدد الأنشطة
Estimating activity resources and durations
The number of work units required to complete the activity.
The total time to complete the activities without including holidays or non-working days.
The calendar time required to complete the activities including holidays and non-working days.
| Staffing | Effort | Duration | Elapsed time |
|---|---|---|---|
| One programmer, 40 hours per week | 80 hours | 10 workdays | 2 weeks |
| Two programmers, each 40 hours per week | 80 hours | 5 workdays | 1 week |
| Two programmers, each 10 hours per week | 80 hours | 20 workdays | 4 weeks |
سؤال سريع
Estimating activity resources and durations
6. Developing the scheduleبناء الجدول
Developing the schedule: Gantt charts, CPM, slack, crashing and fast tracking
Uses results of the other time management processes (activity definition, sequencing, estimating) to determine the start and end date of the project and the planned start and completion dates for each activity. Output: the project schedule.
أدوات بناء الجدول
- Gantt chart
- Critical path method
- Critical chain scheduling
A standard format for displaying project schedule information by listing project activities and their start and finish dates in a calendar format.
| Symbolالرمز | Meaningالمعنى |
|---|---|
| Black diamonds | Milestones |
| Thick black bars | Summary tasks |
| Lighter horizontal bars | Durations of tasks |
| Arrows | Dependencies between tasks |
Slides 48–49
- Sample of Gantt chart (slide 48): tasks A to J drawn as bars over the weeks of May 29, Jun 5, Jun 12 and Jun 19, with arrows from each task to the tasks that depend on it.
- Slide 49 labels a project Gantt chart: WBS hierarchy shown by indentations, summary task, milestone, individual task bar, and arrows show dependencies.
Critical path methodطريقة المسار الحرج
Developing the schedule: Gantt charts, CPM, slack, crashing and fast tracking
- Critical path method (CPM) is a network diagramming technique used to predict total project duration, using the sequence and duration of activities.
- A critical path is the series of activities that determines the earliest time by which the project can be completed.
- The critical path is the longest path through the network diagram — the shortest time the project can be completed. Its activities are critical path activities.
المسألة
Example (the network of slide 52 — the same as ADM example 1).
خطوات الحل
- Path 1 = A, D, G = 15 days
- Path 2 = C, G = 13 days
- Path 3 = B, E, G = 12 days
- Path 4 = B, F = 10 days
النتيجة
Path 1 [A, D, G] is the critical path, because it is the longest path.
Slack and early and late datesالسماحية والتواريخ المبكرة والمتأخرة
Developing the schedule: Gantt charts, CPM, slack, crashing and fast tracking
The amount of time an activity may be delayed without delaying a succeeding activity or the project finish date.
The amount of time an activity can be delayed without delaying the early start of any immediately following activities.
The amount of time an activity may be delayed from its early start without delaying the planned project finish date.
- A forward pass through the network diagram determines the early start and finish dates.
- A backward pass determines the late start and finish dates.
- Total slack = LS − ES, or LF − EF.
- Free slack = early start of next task − early finish of current task.
| Activity | Duration | ES | EF | LS | LF | Total slack | Free slack |
|---|---|---|---|---|---|---|---|
| A | 1 | 0 | 1 | 2 | 3 | 2 | 0 |
| B | 2 | 0 | 2 | 0 | 2 | 0 | 0 |
| C | 3 | 0 | 3 | 2 | 5 | 2 | 0 |
| D | 4 | 1 | 5 | 3 | 7 | 2 | 2 |
| E | 5 | 2 | 7 | 2 | 7 | 0 | 0 |
| F | 4 | 2 | 6 | 9 | 13 | 7 | 7 |
| G | 6 | 3 | 9 | 5 | 11 | 2 | 0 |
| H | 6 | 7 | 13 | 7 | 13 | 0 | 0 |
| I | 2 | 9 | 11 | 11 | 13 | 2 | 2 |
| J | 3 | 13 | 16 | 13 | 16 | 0 | 0 |
Critical path of Project X: B, E, H, J = 16 — the activities with zero total slack.
سؤال سريع
Developing the schedule: Gantt charts, CPM, slack, crashing and fast tracking
Shortening the schedule: crashing and fast trackingتقصير الجدول: الضغط والتسريع
Developing the schedule: Gantt charts, CPM, slack, crashing and fast tracking
If the project duration expands beyond the desired finish date, you can shorten it in two ways:
Crashingالضغط
- A technique for making cost and schedule trade-offs to obtain the greatest amount of schedule compression for the least incremental cost.
- Example: the course-data entry task, estimated at two weeks with a part-time clerk, could be done in one week by having the clerk work full time (or hiring a temporary data entry person).
- Advantage: shortening the time needed to finish a project.
- Disadvantage: it often increases total project costs.
Fast trackingالتسريع
- Doing activities in parallel that you would normally do in sequence (or overlapping them).
- Example: starting some coding before the analysis is completed.
- Advantage: like crashing, it can shorten the time needed to finish a project.
- Disadvantage: it can lengthen the schedule, because starting some tasks too soon often increases project risk and results in rework.
Critical chain schedulingجدولة السلسلة الحرجة
A method that considers limited resources when creating a project schedule, adding duration buffers (non-work schedule activities) to maintain focus on the planned activity durations.
Limited resources happen when:
- Two tasks are planned to occur simultaneously.
- A single piece of equipment is available.
- Equipment is needed full time to complete each task.
Critical chain scheduling suggests:
- Delay one task until the equipment is available (sequential).
- Find another piece of equipment in order to meet the schedule (parallel).
Occurs when a resource works on more than one task at a time. Critical chain scheduling attempts to minimize it: multitasking can delay task completions and often involves wasted setup time, which increases total duration.
Without multitaskingدون تعدد المهام
- Task 1 completed after 10 days
- Task 2 completed after 20 days
- Task 3 completed after 30 days
With multitaskingمع تعدد المهام
- Task 1 completed after 20 days
- Task 2 completed after 25 days
- Task 3 completed after 30 days
Buffers and controlling the scheduleالاحتياطيات والتحكم في الجدول
Critical chain scheduling and controlling the schedule
Additional time to complete a task. In traditional estimates, people often add a buffer and use it whether it is needed or not.
Additional time added before the project's due date.
Additional time added before tasks on the critical path.
Critical chain scheduling removes buffers from individual tasks and creates these buffers instead (slide 78 shows feeding buffers (FB) before the critical chain and a project buffer before the completion date).
7. Controlling the schedule — goals:
- To know the status of the schedule.
- Influence the factors that cause schedule changes.
- Determine that the schedule has changed.
- Manage changes when they occur.
سؤال سريع
Critical chain scheduling and controlling the schedule
الخلاصة
أنهيت الدرس
الخطوة التالية: ثبّت المعلومات بالبطاقات، ثم اختبر نفسك بالأسئلة.
ما راجعته في هذا الدرس
- Project time management and its processesإدارة وقت المشروع وعملياتها
- Planning schedule management and defining activitiesتخطيط إدارة الجدول وتعريف الأنشطة
- Sequencing activities and network diagramsترتيب الأنشطة ومخططات الشبكة
- Estimating activity resources and durationsتقدير موارد الأنشطة ومددها
- Developing the schedule: Gantt charts, CPM, slack, crashing and fast trackingبناء الجدول: جانت والمسار الحرج والسماحية والضغط والتسريع
- Critical chain scheduling and controlling the scheduleجدولة السلسلة الحرجة والتحكم في الجدول