Some standard content:
National Standard of the People's Republic of China
Network Planning Technology
Common Terms
Terms used in network
planning techniques
1 Subject Content and Scope of Application
This standard specifies the commonly used terms and definitions of network planning technology. GB/T 13400. 1--92
This standard is applicable to planning and management work in the fields of industry, agriculture, transportation, infrastructure, defense and scientific research. 2 Terms
2.1 General Terms
2.1.1 Network Diagram Network Diagram is an orderly mesh diagram composed of arrows and nodes to represent a work process. 2.1.2 Network Diagram Work Plan
A schedule compiled by adding time parameters of work to the network diagram. 2.1 3 Network planning techniques Network planning techniques (project network technique:) Network planning is a scientific planning management technique that arranges and controls the progress of tasks to ensure the achievement of specified goals. 2.2 Network planning techniques
2.2.1 Critical path method (CPM) Critical path method All tasks in the plan must be completed according to the established logical relationship, and only a certain duration is estimated for each task.
2.2.2 Program evaluation and review technique (PERT)
Piagram evaluation and review technique All tasks in the plan must be completed according to the established logical relationship, but the duration of the task is not certain. Time parameters should be estimated to evaluate the possibility of completing the task on time. 2.2.3 Overlap network planning method Multiple-delay network planning method In the network plan, there may be multiple sequential relationships between the previous and subsequent tasks. Affirmative network planning technology. Graphical evaluation and review technique (GER) Graphical evaluation and review technique 2. 2. 4
Network planning technique for analyzing tasks and logical relationships between tasks in a plan as random variables, and for which the duration of tasks is uncertain.
Network planning method (DN) Decision network 2.2. 5
Decisions on whether to carry out certain tasks in a plan are made based on the results of the execution of the previous tasks, and the corresponding task completion time and its probability of realization are estimated.
2.2.6 Risk evaluation and review technique (vERT) Network planning technique for analyzing the cost, time and efficiency of a plan in which the logical relationships between tasks and the duration of tasks are uncertain, and for which the probability of possible risks is estimated. 2.2.7 Simulation method for network planning State Technical Supervision Bureau 1992-02-26 Issued 1992-12-01 CB/T 13400.1—92 Network planning technology that uses simulation technology to simulate uncertain work duration 2.2.8 Flow network planning method flowprocssnetwork Work arrangement in planning is based on continuity and balance Network planning method based on the principle of flow operation: 2.3 Network diagram 2.3.1 Types 2.3.1.1 Double-code network diagram (AonA) Activity on-line network diagram with a line or its two ends 2.3.1.2 Single-node network diagram (A-0m-N)
A network diagram that uses nodes or node numbers to represent work. Synonyms: Node-type network diagram
2.3.2 Composition
2.3.2.1 Task
The overall work undertaken by the plan with specified objectives and constraints (time, resource cost, quality, etc.). 2 Project
2. 3. 2. 2
A project with specified objectives and constraints. 3 Artivity
2. 3. 2. 3
A sub-item or sub-task that consumes time or resources according to the detailed procedures of the plan. Synonym: process activity
2. 3.2. 4 virtual work dunimy activity In a double-code network diagram, it only expresses the logical relationship between adjacent previous and next works, and does not consume any time or resources.
2.3.2.5 event
The time point when work starts or is completed in a double-code network diagram. Synonym: event
2.3.2.6 path
The path in a network diagram that starts from the starting node and passes through a series of arrows and nodes in the direction of the arrows, and finally reaches the end node.
Part of path
2. 3. 2. 7
Part of a path in a network diagram.
8 loop luigical loop
The path that starts from a node and goes back to the original starting point along the screen line. Tongwen: Circular National Road
2.3.3 Logical rrlation The order of precedence between work.
2. 3. 3. 1 Prucess relation The order of precedence between productive work determined by process technology, and between non-productive work determined by procedures. 2.3.3.2 Organizational relation The order of precedence between work determined by organizational arrangement needs or case source allocation needs. 2.3.3.3 Front-closely activity The work that is immediately before this work.
Back-up work: arkclasclyactivil
2. 3. 3. 4
The work that is immediately after this work
GB/T 13400. 1--92
2.3.3.5 Parallel activity The work that can be performed simultaneously with this work.
2. 3. 3.6 preceding activities all activities on the line from the starting node to the current activity. 2. 3. 3.7 succeeding activities all activities on the line from the current activity to the end node. 2.3.3.8 startactivity an activity without a preceding activity.
2. 3. 3.9 endactivity an activity with a successor activity.
2. 3. 3. 10 preceding event an event marking the start of one or more activities. 2.3.3.11 succeeding event an event marking the completion of one or more activities. 2.3.3.12 startevent an event starting activity, marking the start of the network diagram. 2.3.3.13 End event
Completion event of the end work. The sign of the end of the network diagram. 2.3. 3.14 Finish to start relationship (FTS) finish to start A sequence relationship in which a certain work is completed or a certain time after the completion of the next work. 2.3.3.15 Start to start relationship (STS) starttostart A sequence relationship in which a certain work starts a certain time after the start of the next work. 6 Finish to finish relationship (FTF) finish to finish 2.3.4.16
A sequence relationship in which a certain work is completed a certain time after the completion of the next work. 2.3.3.17 Start to finish relationship (TF) start to finish A sequence relationship in which a certain work is completed a certain time after the start of the next work. 2.3.4 Symbols
2.3.4.1 Arrow
A solid line with a head at one end in a network diagram. In a double-code network diagram, it represents a sequence of operations; in a single-code network diagram, it represents the logical relationship between operations.
2.3.4.2 Dummy Arrow
A dotted arrowhead at the end of a virtual operation in a double-code network diagram. 2.3.4.3 Inner Arrow
An arrow pointing to a node.
Outward Arrow
An arrow leading from a node,
2.3.4.5 Node ODC
A circle or other closed shape at the end of an arrow in a network diagram. In a double-code network diagram, it represents an event; in a single-code network diagram, it represents a task.
2.3.4.6 Node number (code) nude umber The number given to each node in a nude umber network diagram. In a double-code network diagram, a pair of numbers at the two ends of the arrow line can represent a task. In a single-code network diagram, a number of nodes can represent a task. 2.3.4.7 Starting node prcrding node represents the node that starts an event.
2.3.4.8 Completing node succeeding node represents the node that completes an event.
2.3.4.9 Starting node starinode
The first node of the network diagram,
2. 3. 4. 10 End node cridl norke The last node of the network diagram.
2.3.4.11Dummynode
GB/T 13400. 1—92
A general term for dummy start nodes and dummy end nodes. That is, in a single-code network diagram with multiple start tasks or multiple end tasks, when drawing and calculation require, nodes are set at both ends of the network diagram to represent a dummy start task or a dummy end task.
2Compasite node
2. 3. 4. 12
A node introduced by a bus or where multiple inward arrows converge. BBranrh nade
2. 3. 4. 13
A node that issues a bus or has multiple outward arrows. 2. 3. 4. 14
Decision node ctecixiuni nodle
A node whose subsequent operation is determined by the result of the previous operation. 5 and type nodes ANI)
2. 3. 4. 15
An operation that expresses a logical relationship that the operation after the node must be completed before it can start, or after the work before the node is completed, all the work after the node can be executed. 2.3.4. 16 or type nodes inclusive 0R Lost a node that has a logical relationship that as long as one of the previous items of the work before the node is completed, the work after the node can start regardless of whether the other items are completed, or after the work before the node is completed, one of the items in the work after the node can start. 2.3.4.17F or type node exclusive 0R expresses that as long as there is and can only be one item completed before the node, the work after the node can start or after the work before the node is completed, the node after the node can perform this kind of logical relationship. 2.3.5 Drawing method
2.3.5. 1 gcncratrix method In a network diagram, multiple arrows are drawn into or out of the same node through a common line segment to make the diagram simple. 2.3.5.2 pass-hridge method A drawing method that uses a bridge symbol to avoid confusion caused by cross-hridge lines. 2.3.5.3 directiunal method A drawing method that adds a dotted line pointing circle at the break of the arrow line to indicate the direction of the front line in order to avoid confusion caused by too many cross-arrow lines. 2.4 Network Plan
2.4.1 Classification
2.4.1.1 Classification by Nature
2.4.1.1.1 Telemetric Network Plan A network plan where the work, the logical relationship between the work and the duration of the work are all certain. 2.4.1.1.2 Unterministic Network Plan A network plan where any one or more of the three is uncertain. 2.4.1.2 Destination Classification
2.4.1.2.1 Single-Destination Network A network plan where there is only one destination node. GB/T 13400. 1—92
2.4.1.2.2 Multi-destination network plan multi-destination network plan with more than one destination node
2.4.1.3 Classification by level
2.4.1.3.1 Hierarchical network plan hierarchical network plan with different scopes and degrees of detail compiled according to the needs of different management levels. 2.4.1.3.2 Master network plan master network network plan compiled for the entire planning task. 2.4.1.3.3 Local network plan subnetwork A network plan compiled based on a part of the planned task 2.4.1.4 Classification by expression
2.4.1.4.1 Time-scale network plan titmc-coordinatenetwotk A network plan drawn with time coordinates as the scale, 2.4.1.4.1.1 Time coordinate time-coordinate A coordinate axis that represents the work progress time in a certain unit, 2.4.1.4,2 Non-time-scale network plan nontime-coordinatenetwork A network plan not drawn according to time coordinates. 2.4.2 Time parameters
2.4.2.1 Work duration (D, D,) duration The time specified from the start to the completion of a work. 2.4.2.2 Single-time estimate method single-time estimate A method of estimating only the duration of a work when compiling a fixed network plan. 2.4.2.3 Three-time estimate method three-time estimate A method of determining the duration of a specific work when applying the plan review technique. This method estimates the shortest, longest and most likely duration of a task, and then calculates an expected value as the duration by weighted average. 2.4.2.4 Time simulation method: Time simulation method estimates the upper and lower limits of the duration of a task, and then uses the simulation method to calculate the duration of the task according to its probability distribution.
Synonym: Time simulation method
2.4.2-5 Shortest estimated time (a) optimistictimeesimate The duration required to complete a task under the most favorable conditions. Synonym: Optimistic estimated time
2. 4. 2. 6 Longest estimated time (b) pessinistic time estimate The duration required to complete a task under the most unfavorable conditions, synonym, pessimistic estimated time
2.4.2.7 Most likely estimated time (m) mostlikelytimeestimate The most likely duration to complete a task under normal conditions. 2.4.2.8 Expected activity time The expected value of the work duration calculated by the weighted average method in the three-time estimation method is calculated according to formula (1): De = +4m + 6
Where: D, —
Expected work duration;
— shortest estimated time;
6 — longest estimated time;
— most likely estimated time.
GB/T 13400. 1—92
The probability of completing the work within this time is 50%. 2.4.2.9 Standard deviation of work time (a) standard difference of an activity An indicator to measure the degree of dispersion of the estimated work time. Its value is calculated by formula (2), b
Earliest start time (ES, i, ES.) earlieststarttime 2. 4. 2. 10
The earliest time that the work may start under the constraints of the predecessor work and the relevant time limit. Earliest finish time (EF,,EF,) earliestfinishtime2. 4. 2.11
The earliest time that a task can be completed under the constraints of the predecessor task and related deadlines. 2. 4. 2. 12
2. 4. 2. 13
2. 4. 2. 14
Latest finish time (LF-j, LF)latest finish limeThe latest time that a task must be completed without affecting the timely completion of the task and related deadlines. Latest start time (LS,,LS,)lateststarttimeThe latest time that a task must start without affecting the timely completion of the task and related deadlines. Node time eventtirnc
In a double-code network plan, the time parameter indicating the start or completion time of an event. Synonym, event time
Earliest time of node (El)earliest starttiane2. 4. 2. 15
In a double-code network plan, the earliest concurrent start time of each task after this node. 2.4.2.16
Latest event time of a node (LT,) is the time to complete the previous tasks of the node in the dual generation network planning. 2.4.2.17Standard deviation of the earliest event time of a node: a(Fr,)]standard difference of the earliest event time(2)
is an indicator to measure the degree of discreteness of the earliest event time of a node. Its value is determined by the standard deviation of the working time of all the works on the longest line segment before the node. It is calculated according to formula (3):
α(ET)=
Where. ,,o.,.-oi-l
(ai)2+(o)+-.+(ai-
One node: the standard deviation of the working time of all the preceding works on the longest line segment before the node. 8 The standard deviation of the latest time of the node [aLTstandarddifferenceofhelatcsteventtine2.4.2.18
An indicator to measure the degree of discreteness of the latest time of the node. Its value is determined by the standard deviation of the working time of all the works on the longest line segment after the node, and is calculated according to formula (4):
aL.>={α,)+<-D\++ta)\
Where: o,.d,-1+*0--
The standard deviation of the working time of all the subsequent works on the longest line segment after the node. 2.4.2.19 Probability of event realization (P,) attainableprobability(4)
The probability of a certain event being completed within the specified period PT, must first be calculated according to formula (5) to obtain the corresponding probability factor Z value. PT,-ET,
Where: PT:--specified period;
FT;--earliest time of node:
a(ET,)Standard deviation of earliest time of node
Then according to the value of Z, check the normal distribution table to determine the value. 2.4.2.20 Time difference between different order relationships between tasks. 2.4.2.21 Time difference between completion and start FTS.(5)
GB/T13400.1-92
The time difference between the completion of a task and the start of the task immediately following it. 2.4.2.22 Start-to-start time difference of STS The time difference between the start of a work and the start of its immediate successor. 2.4.2.23 Finish-to-finish time difference of FTF The time difference between the completion of a work and the completion of its immediate successor. Start-to-finish time difference of STF 2.4. 2. 24
The time difference between the start of a work and the completion of its immediate successor. Time lag
2. 4. 2. 25Www.bzxZ.net
The possible difference between the earliest completion time of a work and the earliest start time of its immediate successor in a single-code network plan.
2.4. 2. 26
Time lag
The maneuvering time available for a work or line. 2. 4. 2. 27
2. 4. 2. 28
Total slack (TFTF) total flaat
Under the premise that it does not affect the previous period and related deadlines, a task can use flexible time. Free slack (FF, FF) freefloat
Under the premise that it does not affect the earliest start and related deadlines of its immediate successor task, a task can use flexible time. Dependent slack (DF, -DF,) dependentfloat2. 4. 2. 29
Flexible time that can be used together with the immediate successor task. 2. 4. 2. 301
2. 4. 2. 31
2. 4. 2. 32
Independent slack (IF: IF,) independentfloatTime slack that is unique to this task and cannot be used by the tasks before and after it. Path slack
The total amount of free slack that can be used in a non-critical path. Critical activity
The activity with the least free time in a network plan. Critical event
2. 4. 2. 33
The start and completion events of critical activities.
2. 4. 2. 34
Critical path
The path that consists entirely of critical activities from beginning to end. In a positive network plan, it refers to the path with the longest total duration of activities on the path. In a non-positive network plan, it refers to the path with the lowest estimated completion probability. 2.4.2.35 Time limitation
The time schedule of a network plan or the activities therein is subject to a certain limitation due to external factors. 2.4.2.36 Inferior limitationDnstarttimeThe earliest time limited for the start of a network plan or activities therein. 2.4. 2. 37
SuperiorlimitationunfinishtimeThe latest time for the completion of a network plan or the work therein. 3Restricted time
2. 4. 2. 38
A period of time during which a network plan or the work therein is not allowed to proceed. 2.4.2.39
9Project duration(T)
Generally refers to the time required to complete a task
Calculated project duration2. 4. 2. 40
The duration calculated based on the network plan time parameters. 2.4. 2.41 Required project durationThe duration required by the task principal.
CB/T 13400.1-92
2.4.2.42 Planned project duration The duration determined by comprehensively considering the needs and possibilities on the basis of the required duration and the calculated duration. 2.4.3 Optimization
The process of continuously checking, evaluating, adjusting and completing the network plan according to the established goals under certain constraints. 2.4.3.1 Optimization of duration The process of compressing the calculated duration to achieve the required duration target, or to minimize the duration under certain constraints. 2.4.3.2
Resources
A general term for the manpower, materials, machinery and funds required to complete the task. Resource intensity (t;-jr,)strength of resources2. 4. 3. 3
The number of certain resources required for a work in a unit of time. 2.4.3.4 Resource requirement The sum of the number of certain resources required for each task in a network plan within a certain unit of time. 2.4.3.5 Resource availability The maximum number of certain resources available within a unit of time. 2.4.3.6 Resource limitation - shortest period resource scheduling The process of adjusting the plan to meet resource constraints and minimize delays. 2.4.3.7Fixed construction period-porcelain source balanced resouree leveling
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