Double-target resource-constrained project scheduling method based on time buffering

Abstract

The invention discloses a double-target resource-constrained project scheduling method based on time buffering. The method comprises the following steps: acquiring parameter information of a planned project; based on a pre-constructed proactive scheduling model, performing proactive resource project scheduling analysis on the parameter information to obtain a centralized buffer scheduling plan and a decentralized buffer scheduling plan; wherein the project completion time of the centralized buffer scheduling plan is less than the deadline; based on a pre-constructed reactivity scheduling model, readjusting execution modes and sequences of project activities in the obtained centralized buffer scheduling plan and the decentralized buffer scheduling plan to obtain a target scheduling scheme corresponding to the planned project; and executing project scheduling corresponding to the plan project according to the target adjustment scheme. According to the embodiment of the invention, the project parameters are subjected to data processing by combining proactive and reactive project scheduling, so that double targets of minimizing the adjustment cost and minimizing the completion time are realized, the project scheduling efficiency is improved, and the cost is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of resource-constrained project scheduling, and in particular to a dual-objective resource-constrained project scheduling method, system, terminal and computer storage medium based on time buffering. Background Art

[0002] Project implementationAccurate and effective management of projects is a necessary condition for the success of a project. Project management refers to the planning, execution and coordination of projects by project managers in the form of a team using limited resources to achieve specific project management goals. Project management can help companies deal with complex problems that need to be solved across fields and achieve higher operational efficiency. Among them, project scheduling is an important means to achieve project management. It usually refers to the reasonable allocation of scarce resources such as manpower, materials, and funds under the premise of considering the logical priority relationship of a series of tasks in the project, and arranging the start and end time for each task in the project to achieve one or more goals such as shortening the construction period and reducing costs as much as possible.

[0003] Proactive project scheduling is a robust project scheduling plan formulated before the project starts, taking into account the influence of certain factors. Reactive project scheduling is a highly anti-interference project scheduling plan that is revised in time according to the interference factors that appear during the project implementation. Most current studies only consider proactive project scheduling or reactive project scheduling, but neither of them can make the project scheduling plan optimal. When only reactive scheduling is used to generate a scheduling plan, in the face of uncertain interference factors, the project manager is required to continuously adjust the baseline scheduling plan according to actual changes, which makes it easy for the entire project's time, resources, and other scheduling to inevitably cause confusion, resulting in high project scheduling costs and low efficiency.

[0004] Therefore, the prior art still needs to be improved and developed. Summary of the invention

[0005] The main purpose of the present invention is to provide a dual-objective resource-constrained project scheduling method based on time buffering, which aims to solve the problem of high project scheduling cost and low efficiency due to interference factors in the project scheduling implementation process when only reactive scheduling or only proactive scheduling of robust project scheduling is used to generate a scheduling plan in the prior art.

[0006] A first aspect of an embodiment of the present application provides a dual-objective resource-constrained project scheduling method based on time buffering, and the dual-objective resource-constrained project scheduling method based on time buffering includes the following steps: obtaining parameter information of a planned project; based on a pre-constructed proactive scheduling model, performing proactive resource project scheduling analysis on the parameter information to obtain a centralized buffer scheduling plan and a decentralized buffer scheduling plan; wherein the project completion time of the centralized buffer scheduling plan is less than the deadline; based on a pre-constructed reactive scheduling model, readjusting the execution mode and sequence of the project activities in the centralized buffer scheduling plan and the decentralized buffer scheduling plan to obtain a target scheduling plan corresponding to the planned project; wherein the project activities are activities in the centralized buffer scheduling plan and the decentralized buffer scheduling plan that have not been started when executed according to a predetermined strategy; and executing the project scheduling corresponding to the planned project according to the target adjustment plan.

[0007] Optionally, in one embodiment of the present application, the proactive scheduling model includes a centralized buffer analysis model and a decentralized buffer analysis model;

[0008] The proactive resource project scheduling analysis is performed on the parameter information based on the pre-built proactive scheduling model to obtain a centralized buffer scheduling plan and a decentralized buffer scheduling plan, specifically including:

[0009] Based on the centralized buffer analysis model, a first activity execution plan, a project buffer, and an import buffer corresponding to the plan project are obtained according to the parameter information, and based on the decentralized buffer analysis model, a second activity execution plan and a time buffer corresponding to the plan project are obtained according to the parameter information; wherein the first activity plan satisfies a first constraint, and the second activity execution plan satisfies a second constraint;

[0010] Identify the critical chain and the non-critical chain in the first activity execution plan, insert the corresponding project buffer after the critical chain, and insert the input buffer at the end of the last activity on the non-critical chain to obtain the centralized buffer scheduling plan;

[0011] A time buffer is inserted at the end of each activity in the second activity plan to obtain the distributed buffer scheduling plan.

[0012] Optionally, in one embodiment of the present application, the objective function of the centralized buffer analysis model is:

[0013]

[0014] The objective function of the distributed buffer analysis model is:

[0015] max Robu=β i *Δ i;

[0016] The project starts at: The function of the number of times a project is executed is:

[0017]

[0018] Among them, Z is the start time of the last project activity, is the baseline start time of activity n+1, and the end time of activity n+1 is the project completion time; Robu represents the robustness of the project solution, Δ i The size of the time buffer added to the tail of activity i, β i represents the complexity coefficient of the project grid plan; M is the number of activity modes, m is the mode sequence number, x im B Plan activity execution patterns for proactive scheduling benchmarks.

[0019] Optionally, in one embodiment of the present application, the first constraint includes a first logical relationship constraint and a first updateable resource constraint;

[0020] The function of the first logical relationship constraint is:

[0021]

[0022] The function of the first updateable resource constraint is:

[0023]

[0024] in, Indicates the base start time of the activity. represents the actual duration of activity i when it is executed in mode m. The durations of virtual activities 0 and n+1 are both 0; r imk Indicates the requirement for resource k when executing in mode m, and the resource requirement for virtual activities 0 and n+1 is 0; dual-objective resource-constrained project scheduling based on time buffer represents the critical chain; R k represents the available amount of the kth renewable resource;

[0025] The second constraint includes a second logical relationship constraint and a second updateable resource constraint;

[0026] The function of the second logical relationship constraint is:

[0027]

[0028] The function of the second updatable resource constraint is:

[0029]

[0030] Among them, S jB is the earliest start time of the activity immediately following activity i, S i B and d i are the start time and duration of activity i respectively, and the sum of the two represents the end time of activity i.

[0031] Optionally, in one embodiment of the present application, the function of inserting the corresponding item buffer after the critical chain is:

[0032]

[0033] The function of inserting the last active end of the non-critical chain into the import buffer is:

[0034]

[0035] Among them, PB represents the parameter of the project buffer, δ im represents the safe time of activity i in mode m, β i =1+(N pi -1) / N t Represents the complexity coefficient of project network planning; N pi represents the number of immediate predecessor activities of activity i, N t Indicates the total number of activities for the project; FB l Indicates the parameters of the import buffer;

[0036] The function for inserting a time buffer at the end of each activity in the second activity plan is:

[0037]

[0038] Among them, Δ i A time buffer for activity i.

[0039] Optionally, in one embodiment of the present application, based on the pre-built reactive scheduling model, readjusting the execution mode and sequence of the project activities in the obtained centralized buffer scheduling plan and the obtained decentralized buffer scheduling plan to obtain a target scheduling solution corresponding to the planned project specifically includes:

[0040] Determining, according to the centralized buffer scheduling plan and the decentralized buffer scheduling plan, a unit cost of time deviation from a reference time, an actual activity start time, and an activity planned start time;

[0041] Inputting the unit cost, the actual start time of the activity and the planned start time of the activity into the reactive scheduling model, and outputting a plurality of scheduling schemes to be screened;

[0042] A target scheduling scheme is determined from the plurality of scheduling schemes to be screened.

[0043] Optionally, in one embodiment of the present application, the reactive scheduling model includes a scheduling plan cost objective function and an actual completion time objective function;

[0044] The scheduling plan cost objective function is:

[0045]

[0046] The actual completion time objective function is:

[0047]

[0048] Where f1 represents the deviation cost between the new and old scheduling plans; f2 represents the actual completion time of the project; ω i The unit cost of the actual start time deviating from the baseline time; S i T -S i B is the start time deviation between the old and new scheduling plans, S i T is the actual start time of activity i, S i B is the planned start time of activity i.

[0049] The second aspect of the embodiment of the present application further provides a dual-objective resource-constrained project scheduling system based on time buffer, wherein the dual-objective resource-constrained project scheduling system based on time buffer includes:

[0050] The project parameter acquisition module is used to obtain parameter information of the planned project;

[0051] A centralized and decentralized buffer analysis module, for performing a proactive resource project scheduling analysis on the parameter information based on a pre-built proactive scheduling model, and obtaining a centralized buffer scheduling plan and a decentralized buffer scheduling plan; wherein the project completion time of the centralized buffer scheduling plan is less than the deadline;

[0052] The target scheduling determination module is used to readjust the execution mode and sequence of the unstarted activities in the planned project based on the established reactive scheduling model and the centralized buffer scheduling plan and the decentralized buffer scheduling plan when a resource shortage event occurs, so as to obtain the target scheduling plan corresponding to the planned project.

[0053] The third aspect of an embodiment of the present application also provides a terminal, wherein the terminal includes: a memory, a processor, and a time-buffered dual-objective resource-constrained project scheduling program stored in the memory and executable on the processor, wherein the time-buffered dual-objective resource-constrained project scheduling program implements the steps of the time-buffered dual-objective resource-constrained project scheduling method based on time buffering when executed by the processor.

[0054] The fourth aspect of an embodiment of the present application also provides a computer-readable storage medium, wherein the computer-readable storage medium stores a dual-objective resource-constrained project scheduling program based on time buffering, and when the dual-objective resource-constrained project scheduling program based on time buffering is executed by a processor, the steps of the dual-objective resource-constrained project scheduling method based on time buffering as described above are implemented.

[0055] Beneficial effects: The present invention provides a dual-objective resource-constrained project scheduling method based on time buffering. The method processes project parameters by combining proactive and reactive project scheduling to achieve the dual objectives of minimizing adjustment costs and minimizing completion time, enriches the diversity of proactive-reactive equilibrium models, meets the needs of controlling projects from different dimensions and aspects, improves the efficiency of project scheduling and reduces costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0057] Figure 1 It is a flow chart of a preferred embodiment of the dual-objective resource-constrained project scheduling method based on time buffering of the present application;

[0058] Figure 2 It is a flowchart of specific implementation steps of the entire execution process in a preferred embodiment of the dual-objective resource-constrained project scheduling method based on time buffering of the present application;

[0059] Figure 3 It is a schematic diagram of a proactive scheduling plan for centralized buffering in a proactive scheduling model in an embodiment of the present application;

[0060] Figure 4 It is a schematic diagram of a proactive scheduling plan for distributed buffering in a proactive scheduling model in an embodiment of the present application.

[0061] Figure 5It is a structural schematic diagram of a preferred embodiment of the dual-objective resource-constrained project scheduling system based on time buffering of the present application;

[0062] Figure 6 This is a schematic diagram of the structure of a preferred embodiment of the terminal of the present application.

[0063] Description of reference numerals:

[0064] 10. Dual-objective resource-constrained project scheduling system based on time buffer; 100. Project parameter acquisition module; 200. Centralized and decentralized buffer analysis module; 300. Target scheduling determination module. DETAILED DESCRIPTION

[0065] In order to make the purpose, technical scheme and effect of the present invention clearer and more specific, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. The described embodiments are only possible technical implementations of the present invention, not all possible implementations. Based on the embodiments of the present invention, those skilled in the art can completely combine the embodiments of the present invention to obtain other embodiments without creative work, and these embodiments are also within the scope of protection of the present invention.

[0066] In the related art, when only reactive scheduling is used to generate a scheduling plan, in the face of uncertain interference factors, the project manager is required to continuously adjust the benchmark scheduling plan according to the actual changes, which makes the scheduling of time, resources, etc. of the entire project inevitable. Therefore, it is very necessary to estimate the factors that may affect the scheduling of the entire project in the project planning stage, and use the proactive scheduling method of robust project scheduling to formulate a benchmark scheduling plan so that the scheduling plan has strong stability during the actual operation process. However, unexpected interference factors often appear in the project execution stage. Even if the uncertain factors are fully considered before the project is implemented, and the robustness value of the benchmark scheduling plan is high, it is actually impossible to completely avoid the interference in the project scheduling implementation process. Therefore, in order to better avoid the impact of unpredictable and possible uncertain factors on the project scheduling process during the project implementation, it is very necessary to use the reactive scheduling method to optimize and adjust the benchmark scheduling plan generated by the proactive scheduling method. At present, there are few studies that combine proactive and reactive project scheduling. Existing studies mostly target the robust cost of proactive scheduling and the adjustment cost of reactive scheduling under uncertain environments, but do not conduct in-depth research on the impact of the robustness of proactive scheduling on the reactive scheduling objectives.

[0067] The main disadvantage of the existing technology is that most studies only consider proactive project scheduling or reactive project scheduling, neither of which can make the project scheduling plan optimal. If only reactive scheduling is used to generate a scheduling plan, in the face of uncertain interference factors, the project manager is required to continuously adjust the baseline scheduling plan according to actual changes, which will cause chaos in the scheduling of time, resources, etc. of the entire project. On the other hand, although the factors that may affect the scheduling of the entire project can be estimated in the project planning stage, and the proactive scheduling method of robust project scheduling can be used to formulate a baseline scheduling plan so that the scheduling plan has strong stability during the actual operation process, unexpected interference factors often appear in the project execution stage. Even if the uncertain factors are fully considered before the project is implemented, and the robustness value of the benchmark scheduling plan is high, it is actually impossible to completely avoid the interference in the implementation of project scheduling.

[0068] The embodiment of the present application combines proactive and reactive project scheduling to achieve the dual goals of minimizing adjustment costs and minimizing completion time. The method first improves the robustness of project scheduling by setting a certain time buffer or resource buffer in the scheduling plan to cope with the impact of uncertain factors on the project, and then performs reactive scheduling optimization based on the deviation cost between the new and old scheduling plans and the actual completion time of the project.

[0069] The embodiments of the present application improve the rationality and economy of project scheduling by establishing a proactive scheduling model with the goal of maximizing robustness, and a reactive scheduling model with the goal of minimizing costs and project completion time.

[0070] The following describes the dual-objective resource-constrained project scheduling method based on time buffering of the embodiment of the present application with reference to the accompanying drawings. In view of the problem that when only reactive scheduling or only proactive scheduling of robust project scheduling is used to generate a scheduling plan in the above-mentioned related technologies, the interference factors in the implementation process of project scheduling lead to high project scheduling costs and low efficiency, the present application provides a dual-objective resource-constrained project scheduling method based on time buffering, in which data processing of project parameters is performed by combining proactive and reactive project scheduling to achieve the dual goals of minimizing adjustment costs and minimizing completion time, enriching the diversity of proactive-reactive equilibrium models, meeting the needs of projects to control projects from different dimensions and aspects, improving the efficiency of project scheduling and reducing costs. Thus, the technical problem that when only reactive scheduling or only proactive scheduling of robust project scheduling is used to generate a scheduling plan in the related technologies, the interference factors in the implementation process of project scheduling lead to high project scheduling costs and low efficiency.

[0071] The embodiments of the present application obtain project content and required results; establish a proactive resource-constrained project scheduling model; analyze the centralized buffer method; analyze the decentralized buffer method; establish a reactive resource-constrained dual-objective scheduling model; obtain project goals and performance, and use the designed model for analysis to provide a reference basis for project creation and selection of project plans, thereby meeting the needs of controlling projects from different dimensions and aspects, and at the same time meeting specific needs when facing uncertain environments in project practice.

[0072] The technical solution of the present invention is described in detail with specific embodiments below. The following specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described in detail in some embodiments.

[0073] First, obtain project-related parameters, such as the number of activities, the number of activity modes, etc. Secondly, conduct proactive resource project scheduling analysis, and calculate the running time of specific projects through the centralized buffer model and decentralized buffer model established in this part. Third, input the above-obtained time into the reactive resource-constrained dual-objective scheduling model to calculate the deviation between the scheduling plans and the actual completion time. Finally, output the best scheduling plan for the input project.

[0074] The embodiments of the present application control the robustness of proactive scheduling, thereby having a dual impact on the cost and time of reactive scheduling plans, thereby meeting specific needs in uncertain environments in project practice.

[0075] The dual-objective resource-constrained project scheduling method based on time buffering described in the preferred embodiment of the present invention is as follows: Figure 1 As shown, the dual-objective resource-constrained project scheduling method based on time buffer includes the following steps:

[0076] In step S101, parameter information of the planned project is obtained, including the number of project activities, the number of activity modes, the activity execution mode, logical constraints and resource constraints.

[0077] Specifically, collect the number of all activities in the project and the possible execution modes of each activity, determine the logical relationship and resource constraints between activities, including the execution time of activities, resource usage, etc.

[0078] Table 1 shows the relevant parameters and their meanings used in the examples of this application:

[0079]

[0080]

[0081] In step S102, based on a pre-constructed proactive scheduling model, a proactive resource project scheduling analysis is performed on the parameter information to obtain a centralized buffer scheduling plan and a decentralized buffer scheduling plan; wherein the project completion time of the centralized buffer scheduling plan is less than the deadline.

[0082] In a possible implementation, based on the centralized buffer analysis model, the first activity execution plan, project buffer and import buffer corresponding to the planned project are obtained according to the parameter information, and based on the decentralized buffer analysis model, the second activity execution plan and time buffer corresponding to the planned project are obtained according to the parameter information; wherein, the first activity plan satisfies the first constraint and the second activity execution plan satisfies the second constraint; the critical chain and non-critical chain in the first activity execution plan are identified, the corresponding project buffer is inserted after the critical chain, and the import buffer is inserted at the end of the last activity on the non-critical chain to obtain the centralized buffer scheduling plan; the time buffer is inserted at the end of each activity in the second activity plan to obtain the decentralized buffer scheduling plan.

[0083] Specifically, the proactive resource-constrained project scheduling model (ie, proactive scheduling model) includes: centralized buffer method analysis (centralized buffer analysis model) and decentralized buffer method analysis (decentralized buffer analysis model).

[0084] Centralized buffer method: The centralized buffer method includes key chain technology addition; key chain end item buffer addition; non-critical chain end import buffer addition.

[0085] The centralized buffering method is specifically defined. First, the objective function of this part is defined as

[0086]

[0087] Where z is the start time of the last project activity, S i B is the baseline start time of activity i. Since this activity is a virtual activity, the end time of n+1 is the project completion time.

[0088] Secondly, define the project start time and the project execution times function as:

[0089]

[0090] Where M is the number of active modes, m is the mode number, and x im B The proactive scheduling benchmark plans the activity execution mode, where if activity i adopts execution mode m, then x im B =1; otherwise, x im B =0.

[0091] The function that satisfies the end-start type logical relationship constraints and renewable resource constraints between activities is:

[0092]

[0093] Among them, d im represents the actual duration of activity i when it is executed in mode m, where the durations of virtual activities 0 and n+1 are both 0; r imk represents the amount of resource k required when executing in mode m. The resource requirements of virtual activities 0 and n+1 are 0. CC represents the critical chain. R k Represents the available amount of the kth renewable resource.

[0094] The buffer function of the critical chain end item and the buffer technology function of the non-critical chain end import are:

[0095]

[0096] Among them, δ im represents the safe time of activity i under mode m, which is half of the total duration of the activity; β i =1+(N pi -1) / N t Represents the complexity coefficient of project network planning; N pi represents the number of immediate predecessor activities of activity i, N t Represents the total number of activities for the project.

[0097] The rest include sequential constraints, project deadline constraints, and reality constraints as follows:

[0098]

[0099]

[0100]

[0101] The project deadline is calculated based on the centralized buffer analysis model. When the project completion time is less than or equal to the project deadline, the corresponding execution can be performed. The quality robustness of this part is mainly composed of the contribution of the project buffer to the robustness. However, the insertion of the inbound buffer will cause the key activities to be pushed back, which will delay the overall completion time of the project and occupy the project buffer. Therefore, the inbound buffer reduces the robustness of the project quality. However, the inbound buffer takes into account the robustness of the project to a certain extent, provides a safe time for the delay of activities on the non-critical chain, and reduces the possibility of delaying the start time of the key activities immediately after the inbound buffer.

[0102] Specifically, the distributed buffer analysis model is as follows:

[0103] First, define the objective function:

[0104] max Robu=β i *Δ i ;

[0105] Among them, this part represents the robustness of the solution of the project, which is composed of the product of two parts, Δ i The time buffer size added to the end of activity i is not greater than the difference between the latest start time and the earliest start time of activity i; β i =1+(N pi -1) / N t Represents the project grid planning complexity coefficient.

[0106] Define the project start time and project execution times as follows:

[0107]

[0108]

[0109] The function that satisfies the end-start type logical relationship constraints and renewable resource constraints between activities is:

[0110]

[0111]

[0112] The time buffer function for activity i is:

[0113]

[0114] Among them, S j B is the earliest start time of the activity immediately following activity i, S i B and d i are the start time and duration of activity i, respectively. The sum of the two represents the end time of activity i. To avoid delaying the earliest start time of the subsequent activity j, a time buffer Δ i The sum of the actual end time of activity i does not exceed the latest end time of activity i.

[0115] The project deadline constraint and reality constraint functions are:

[0116]

[0117]

[0118] The activity start time, resource availability, and activity duration are all no less than 0. im=1, indicating that activity j is in execution mode m, otherwise it means that it is not executed. In proactive scheduling, the idea of ​​decentralized buffering is used to add buffers to reduce the interference of some uncertain factors. Time buffers are added in a decentralized buffering manner, that is, the shortest duration of each project activity is calculated without considering interference factors, and the difference between the project's planned completion date and the shortest duration is used as the maximum buffer time of the project, and is allocated to the end of each activity.

[0119] It should be noted that the constraints (including the first constraint and the second constraint) include:

[0120] First, the project consists of n+2 activities, where activity 0 and activity n+1 are virtual activities, representing the start and end of the project, respectively, and their duration and resource requirements are both 0;

[0121] Second, the activities must satisfy the zero-delay, finish-start precedence constraints, that is, the start time of all activities must not be earlier than the finish time of their predecessor activities;

[0122] Third, only renewable resources are considered, that is, the supply of resources at each moment of project execution is limited and fixed and will not be consumed as the project progresses;

[0123] Fourth, activities in the project are not allowed to be preempted during execution, and the execution mode of ongoing activities cannot be switched:

[0124] Fifth, when the proactive scheduling plan is based on the centralized buffer method, during the project execution, the actual start time of the activity cannot be earlier than the planned start time, that is, follow the corresponding scheduling rules; when the proactive scheduling plan is based on the decentralized buffer method, during the project execution, the actual start time of the activity can be earlier than the planned start time, and follow the corresponding scheduling rules.

[0125] The embodiments of the present application adopt centralized buffer model calculation and decentralized buffer model calculation: by adding time buffer, the completion time of the project under centralized buffer conditions is calculated. If the project completion time is less than or equal to the deadline, execution continues; by adding time buffer in decentralized buffer mode, the time robustness of the project is calculated to improve the accuracy of time calculation.

[0126] That is to say, the proactive resource-constrained project scheduling in the embodiment of the present application is divided into centralized buffer proactive scheduling and decentralized buffer proactive scheduling. By setting a certain time buffer or resource buffer in the scheduling plan to cope with the impact of uncertain factors on the project, the robustness of the project scheduling is improved.

[0127] Among them, centralized buffer proactive scheduling reduces the robustness of project quality by adding time buffer. By inputting parameters such as the number of project activities, the number of activity modes, the activity execution mode, related logical constraints and resource constraints, and calculating through a given functional relationship, the project completion time under the added time buffer is obtained. When the project completion time is less than or equal to the project deadline, the corresponding execution can be performed.

[0128] Distributed buffer proactive scheduling reduces the interference of some uncertain factors by adding distributed buffers, in which time buffers are added in the form of distributed buffers to improve the accuracy of time calculation. By inputting the time buffer size, which is not greater than the difference between the latest and earliest start times of the activity; the earliest start time of the project; the latest start time of the project; the start time and duration of the activity, etc., the robustness of time under the distributed buffer condition is obtained by calculating the point function relationship.

[0129] In step S103, based on the established reactive scheduling model, according to the centralized buffer scheduling plan and the decentralized buffer scheduling plan, when a resource shortage event occurs, the execution mode and sequence of the unstarted activities in the planned project are readjusted to obtain the target scheduling plan corresponding to the planned project; wherein, the project activities are the activities that have not been started when the centralized buffer scheduling plan and the decentralized buffer scheduling plan are executed according to the predetermined strategy.

[0130] In a possible implementation, based on the centralized buffer scheduling plan and the decentralized buffer scheduling plan, the unit cost of the time deviation from the reference time, the actual start time of the activity, and the planned start time of the activity are determined; the unit cost, the actual start time of the activity, and the planned start time of the activity are input into the reactive scheduling model, and a plurality of scheduling schemes to be screened are output; and a target scheduling scheme is determined from the plurality of scheduling schemes to be screened.

[0131] Specifically, a reactive resource-constrained dual-objective scheduling model (i.e., a reactive scheduling model) is established, and the reactive resource-constrained dual-objective scheduling model includes two objective functions, which are set as f1 and f2, respectively, where f1 represents the deviation cost between the new and old scheduling plans; and f2 represents the actual completion time of the project. The two reactive scheduling optimization sub-models are shown below.

[0132] First, the scheduling plan cost and time objective functions are as follows.

[0133]

[0134]

[0135] ω i The unit cost of the actual start time deviating from the baseline time; Si T -S i B is the start time deviation between the old and new scheduling plans, where S i T is the actual start time of activity i, S i B is the planned start time of activity i.

[0136] The consistency function of the activity start time and the benchmark schedule and the activity execution count function are as follows:

[0137]

[0138]

[0139] The execution count function ensures that each activity is completed once in one execution mode.

[0140] The end-start type logical relationship constraint function, renewable resource constraint function and proficiency constraint function between activities are as follows:

[0141]

[0142]

[0143]

[0144] The activity start time, resource availability, and activity duration are all no less than 0. im =1, indicating that activity j is in execution mode m, otherwise it means no execution. In the project planning stage, considering the influence of uncertain factors on the actual execution process of the project, a robust benchmark scheduling plan with a time buffer to resist interference events is generated, which is called a proactive project scheduling plan. However, the performance of the plan still needs to be tested after the specific interference event occurs. Therefore, this paper proposes to use a reactive scheduling strategy for dealing with the impact of interference events to test two robust forms of two proactive scheduling plans: quality robustness and solution robustness.

[0145] The embodiment of the present application is run through input data and a reactive scheduling model, where the input data includes the unit cost of time deviation from the baseline time, the actual start time of the activity, and the planned start time; the reactive scheduling model readjusts the execution mode and sequence of the unstarted activities based on the results of the proactive scheduling plan when a resource shortage event occurs to meet the constraint that the actual start time is not less than the planned start time; from all generated plans, the plan with the smallest activity start time deviation and the smallest project completion time in the proactive scheduling plan is selected as the final plan.

[0146] That is to say, the reactive resource-constrained dual-objective scheduling, through the corresponding input, obtains the deviation cost between the new and old scheduling plans, as well as the actual completion time of the project. The input includes the unit cost of the time deviation from the benchmark time, the actual start time of the activity, and the planned start time of the activity. In the project planning stage, the reactive constrained dual-objective scheduling can be used to generate a robust benchmark scheduling plan with a time buffer to resist interference events.

[0147] In step S104, the project scheduling corresponding to the planned project is executed according to the target adjustment plan.

[0148] Specifically, for project activities that have not started when the centralized buffer scheduling plan and the decentralized buffer scheduling plan are executed according to the predetermined strategy, the corresponding project scheduling shall be executed according to the target adjustment plan.

[0149] like Figure 2 , Figure 3 and Figure 4 As shown, the above-mentioned dual-objective resource-constrained project scheduling method based on time buffer of the present invention is further described below through specific embodiments:

[0150] First, in the first part, the model is run for the centralized buffer proactive scheduling plan. The running steps are as follows: Figure 3 As shown, define the objective function, define the project start time, define the constraints, output the initial start time list of activities under the constraints, and form the initial activity execution plan, where Each activity is required to select only one execution mode, that is, each activity in the scheduling plan corresponds to a set of duration and resource usage; Activities on the same critical chain or non-critical chain must meet the logical sequence; It is required that the total resource usage of activities per unit time does not exceed the resource supply; The project completion time is required not to exceed the completion time agreed in the contract.

[0151] Secondly, based on the initial execution plan, the critical chain and non-critical chain are identified, and the corresponding project buffer is inserted after the critical chain. Calculated; insert the corresponding input buffer at the intersection of each non-critical chain and the critical chain, and its parameters are Calculated and should satisfy the constraints

[0152] In non-critical chain NC lAfter the end of the last activity i is inserted into the import buffer, there is no resource conflict with the activity j on the critical chain CC. To meet this condition, the start time of activity j on the critical chain can be postponed to make it not less than the completion time of the import buffer; if the start time of the activity on the critical chain is postponed, the critical chain and the project buffer will be postponed as a whole, but not exceeding the contractual agreed time. Finally, a proactive scheduling plan based on centralized buffer with the minimum project completion time is obtained.

[0153] In the second part, the model of the distributed buffer proactive scheduling plan is run. The objective function is defined as and the constraints of the distributed buffer scheduling model are defined. The running steps are as follows: Figure 4 As shown. Output the initial start time list of activities under the constraints to form the initial activity execution plan. Each activity is required to select only one execution mode, that is, each activity corresponds to only one set of duration and resource usage in the scheduling plan; Constraints that activities on the same critical chain or non-critical chain must satisfy this logical order; Constrain the total resource usage of activities per unit time to not exceed the resource supply; The completion time of the constraint project does not exceed the completion time agreed in the contract. Then, based on the initial execution plan, a time buffer is inserted at the end of each activity, and the weighted buffer sum of each plan is calculated, and its weight is Npi represents the number of activities immediately preceding activity i, and Nt represents the total number of project activities. The buffer size is expressed as After the model calculation, the plan with weighted buffer and minimum output is selected as the decentralized buffer scheduling plan.

[0154] The third part is the reactive scheduling model calculation. The input of this part is the proactive scheduling plan results of the first and second parts. When a resource shortage event occurs, the execution order and execution mode of the activities that have been completed according to the plan will not be changed. For activities that have not started, their execution mode and execution order can be readjusted without following the proactive scheduling plan, but the actual start time of the activity must not be less than the planned start time. The constraint is There is only one execution mode for an activity: Activities must be satisfied To constrain the logical relationship; The total usage of activity resources per unit time is determined, and the total usage of activity resources per unit time does not exceed the resource supply.

[0155] Finally, among all the generated plans, the plan with the smallest deviation of activity start time from the proactive scheduling plan and the smallest project completion time in the decentralized buffer scheduling model is selected as the final plan to schedule the corresponding project.

[0156] Next, a dual-objective resource-constrained project scheduling system based on time buffering proposed according to an embodiment of the present application is described with reference to the accompanying drawings.

[0157] Figure 5 It is a block diagram of a dual-objective resource-constrained project scheduling system based on time buffering according to an embodiment of the present application.

[0158] like Figure 5 As shown, the dual-objective resource-constrained project scheduling system 10 based on time buffering includes: a project parameter acquisition module 100 , a centralized and decentralized buffer analysis module 200 , and a target scheduling determination module 300 .

[0159] Specifically, the project parameter acquisition module 100 is used to obtain parameter information of the planned project;

[0160] The centralized and decentralized buffer analysis module 200 is used to perform a proactive resource project scheduling analysis on the parameter information based on a pre-built proactive scheduling model to obtain a centralized buffer scheduling plan and a decentralized buffer scheduling plan; wherein the project completion time of the centralized buffer scheduling plan is less than the deadline;

[0161] The target scheduling determination module 300 is used to readjust the execution mode and sequence of the unstarted activities in the planned project based on the established reactive scheduling model and the centralized buffer scheduling plan and the decentralized buffer scheduling plan when a resource shortage event occurs, so as to obtain the target scheduling plan corresponding to the planned project.

[0162] Figure 6 A schematic diagram of the structure of a terminal provided in an embodiment of the present application. The terminal may include:

[0163] A memory 501 , a processor 502 , and a computer program stored in the memory 501 and executable on the processor 502 .

[0164] When the processor 502 executes the program, the dual-objective resource-constrained project scheduling method based on time buffering provided in the above embodiment is implemented.

[0165] Furthermore, the terminal further includes:

[0166] The communication interface 503 is used for communication between the memory 501 and the processor 502 .

[0167] The memory 501 is used to store computer programs that can be executed on the processor 502 .

[0168] The memory 501 may include a high-speed RAM memory, and may also include a non-volatile memory (non-volatile memory), such as at least one disk memory.

[0169] If the memory 501, the processor 502 and the communication interface 503 are implemented independently, the communication interface 503, the memory 501 and the processor 502 can be connected to each other through a bus and communicate with each other. The bus can be an Industry Standard Architecture (ISA) bus, a Peripheral Component (PCI) bus or an Extended Industry Standard Architecture (EIS) bus. The bus can be divided into an address bus, a data bus, a control bus, etc. For ease of representation, Figure 6 Only one thick line is used in the diagram, but this does not mean that there is only one bus or only one type of bus.

[0170] Optionally, in a specific implementation, if the memory 501, the processor 502 and the communication interface 503 are integrated on a chip, the memory 501, the processor 502 and the communication interface 503 can communicate with each other through an internal interface.

[0171] The processor 502 may be a central processing unit (CPU), or an application specific integrated circuit (ASIC), or one or more integrated circuits configured to implement the embodiments of the present application.

[0172] This embodiment also provides a computer-readable storage medium on which a computer program is stored. When the program is executed by a processor, the dual-objective resource-constrained project scheduling method based on time buffering is implemented as described above.

[0173] One embodiment of the present application provides a computer program product, including a computer program, which, when executed by a processor, implements the present application Figure 1 A dual-objective resource-constrained project scheduling method based on time buffer is provided in any of the corresponding embodiments.

[0174] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or N embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0175] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of this application, "N" means at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0176] Any process or method description in a flowchart or otherwise described herein may be understood to represent a module, fragment or portion of code comprising one or N executable instructions for implementing the steps of a custom logical function or process, and the scope of the preferred embodiments of the present application includes alternative implementations in which functions may not be performed in the order shown or discussed, including performing functions in a substantially simultaneous manner or in reverse order depending on the functions involved, which should be understood by technicians in the technical field to which the embodiments of the present application belong.

[0177] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as an ordered list of executable instructions for implementing logical functions, and can be embodied in any computer-readable storage medium for use by an instruction execution system, device or apparatus (such as a computer-based system, a system including a processor, or other system that can fetch instructions from an instruction execution system, device or apparatus and execute instructions), or in combination with these instruction execution systems, devices or apparatuses. For the purposes of this specification, a "computer-readable storage medium" can be any device that can contain, store, communicate, propagate or transmit a program for use by an instruction execution system, device or apparatus, or in combination with these instruction execution systems, devices or apparatuses. More specific examples (non-exhaustive list) of computer-readable storage media include the following: an electrical connection with one or N wirings (electronic device), a portable computer disk box (magnetic device), a random access memory (RAM), a read-only memory (ROM), an erasable and programmable read-only memory (EPROM or flash memory), a fiber optic device, and a portable compact disk read-only memory (CDROM). In addition, the computer-readable storage medium may even be paper or other suitable medium on which the program is printed, since the program can be obtained electronically by optically scanning the paper or other medium and then editing, interpreting or processing in other suitable ways as necessary, and then storing it in a computer memory.

[0178] It should be understood that the various parts of the present application can be implemented by hardware, software, firmware or a combination thereof. In the above-mentioned embodiment, the N steps or methods can be implemented by software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented by hardware, as in another embodiment, it can be implemented by any one of the following technologies known in the art or their combination: a discrete logic circuit having a logic gate circuit for implementing a logic function for a data signal, a dedicated integrated circuit having a suitable combination of logic gate circuits, a programmable gate array (PGA), a field programmable gate array (FPGA), etc.

[0179] A person skilled in the art may understand that all or part of the steps in the method for implementing the above-mentioned embodiment may be completed by instructing related hardware through a program, and the program may be stored in a computer-readable storage medium, which, when executed, includes one or a combination of the steps of the method embodiment.

[0180] In addition, each functional unit in each embodiment of the present application may be integrated into a processing module, or each unit may exist physically separately, or two or more units may be integrated into one module. The above-mentioned integrated module may be implemented in the form of hardware or in the form of a software functional module. If the integrated module is implemented in the form of a software functional module and sold or used as an independent product, it may also be stored in a computer-readable storage medium.

[0181] The storage medium mentioned above may be a read-only memory, a magnetic disk or an optical disk, etc. Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limiting the present application. A person of ordinary skill in the art may change, modify, replace and modify the above embodiments within the scope of the present application.

[0182] It should be understood that the application of the present application is not limited to the above examples. For ordinary technicians in this field, improvements or changes can be made based on the above description. All these improvements and changes should fall within the scope of protection of the claims attached to this application.

[0183] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit it. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A dual-objective resource-constrained project scheduling method based on time buffer, characterized in that: include: Get parameter information of planned projects; Based on the pre-built proactive scheduling model, a proactive resource project scheduling analysis is performed on the parameter information to obtain a centralized buffer scheduling plan and a decentralized buffer scheduling plan; wherein the project completion time of the centralized buffer scheduling plan is less than the deadline; Based on the pre-built reactive scheduling model, the execution mode and order of the project activities in the centralized buffer scheduling plan and the decentralized buffer scheduling plan are readjusted to obtain a target scheduling scheme corresponding to the planned project; wherein the project activities are activities that have not been started when the centralized buffer scheduling plan and the decentralized buffer scheduling plan are executed according to a predetermined strategy; Execute the project scheduling corresponding to the planned project according to the target adjustment plan.

2. The dual-objective resource-constrained project scheduling method based on time buffer according to claim 1 is characterized in that: The proactive scheduling model includes a centralized buffer analysis model and a decentralized buffer analysis model; The proactive resource project scheduling analysis is performed on the parameter information based on the pre-built proactive scheduling model to obtain a centralized buffer scheduling plan and a decentralized buffer scheduling plan, specifically including: Based on the centralized buffer analysis model, a first activity execution plan, a project buffer, and an import buffer corresponding to the plan project are obtained according to the parameter information, and based on the decentralized buffer analysis model, a second activity execution plan and a time buffer corresponding to the plan project are obtained according to the parameter information; wherein the first activity plan satisfies a first constraint, and the second activity execution plan satisfies a second constraint; Identify the critical chain and the non-critical chain in the first activity execution plan, insert the corresponding project buffer after the critical chain, and insert the input buffer at the end of the last activity on the non-critical chain to obtain the centralized buffer scheduling plan; A time buffer is inserted at the end of each activity in the second activity plan to obtain the distributed buffer scheduling plan.

3. The dual-objective resource-constrained project scheduling method based on time buffer according to claim 2 is characterized in that: The objective function of the centralized buffer analysis model is: The objective function of the distributed buffer analysis model is: max Robu=β i *D i ; The project starts at: The function of the number of times a project is executed is: Among them, Z is the start time of the last project activity, is the baseline start time of activity n+1, and the end time of activity n+1 is the project completion time; Robu represents the robustness of the project solution, Δ i The size of the time buffer added to the tail of activity i, β i represents the complexity coefficient of the project grid plan; M is the number of activity modes, m is the mode sequence number, x im B Plan activity execution patterns for proactive scheduling benchmarks.

4. The dual-objective resource-constrained project scheduling method based on time buffer according to claim 3 is characterized in that: The first constraint includes a first logical relationship constraint and a first updateable resource constraint; The function of the first logical relationship constraint is: or The function of the first updateable resource constraint is: in, Indicates the base start time of the activity. represents the actual duration of activity i when it is executed in mode m. The durations of virtual activities 0 and n+1 are both 0; r imk Indicates the requirement for resource k when executing in mode m, and the resource requirement for virtual activities 0 and n+1 is 0; dual-objective resource-constrained project scheduling based on time buffer represents the critical chain; R k represents the available amount of the kth renewable resource; The second constraint includes a second logical relationship constraint and a second updateable resource constraint; The function of the second logical relationship constraint is: The function of the second updatable resource constraint is: Among them, S j B is the earliest start time of the activity immediately following activity i, S i B and d i are the start time and duration of activity i respectively, and the sum of the two represents the end time of activity i.

5. The dual-objective resource-constrained project scheduling method based on time buffer according to claim 4 is characterized in that: The function of inserting the corresponding item buffer behind the critical chain is: The function of inserting the last active end of the non-critical chain into the import buffer is: Among them, PB represents the parameter of the project buffer, δ im represents the safe time of activity i in mode m, β i =1+(N pi -1) / N t Represents the complexity coefficient of project network planning; N pi represents the number of immediate predecessor activities of activity i, N t Indicates the total number of activities for the project; FB l Indicates the parameters of the import buffer; The function for inserting a time buffer at the end of each activity in the second activity plan is: Among them, Δ i A time buffer for activity i.

6. The dual-objective resource-constrained project scheduling method based on time buffer according to any one of claims 1 to 5, characterized in that: The method of re-adjusting the execution mode and sequence of the project activities in the centralized buffer scheduling plan and the decentralized buffer scheduling plan based on the pre-built reactive scheduling model to obtain a target scheduling solution corresponding to the planned project specifically includes: Determining, according to the centralized buffer scheduling plan and the decentralized buffer scheduling plan, a unit cost of time deviation from a reference time, an actual activity start time, and an activity planned start time; Inputting the unit cost, the actual start time of the activity and the planned start time of the activity into the reactive scheduling model, and outputting a plurality of scheduling schemes to be screened; A target scheduling scheme is determined from the plurality of scheduling schemes to be screened.

7. The dual-objective resource-constrained project scheduling method based on time buffer according to claim 6 is characterized in that: The reactive scheduling model includes a scheduling plan cost objective function and an actual completion time objective function; The scheduling plan cost objective function is: The actual completion time objective function is: Where f1 represents the deviation cost between the new and old scheduling plans; f2 represents the actual completion time of the project; ω i The unit cost of the actual start time deviating from the baseline time; S i T -S i B is the start time deviation between the old and new scheduling plans, S i T is the actual start time of activity i, S i B is the planned start time of activity i.

8. A dual-objective resource-constrained project scheduling system based on time buffer, characterized in that: The dual-objective resource-constrained project scheduling system based on time buffering includes: The project parameter acquisition module is used to obtain parameter information of the planned project; A centralized and decentralized buffer analysis module, for performing a proactive resource project scheduling analysis on the parameter information based on a pre-built proactive scheduling model, and obtaining a centralized buffer scheduling plan and a decentralized buffer scheduling plan; wherein the project completion time of the centralized buffer scheduling plan is less than the deadline; The target scheduling determination module is used to readjust the execution mode and sequence of the unstarted activities in the planned project based on the established reactive scheduling model and the centralized buffer scheduling plan and the decentralized buffer scheduling plan when a resource shortage event occurs, so as to obtain the target scheduling plan corresponding to the planned project.

9. A terminal, characterized in that: The terminal includes: a memory, a processor, and a dual-objective resource-constrained project scheduling program based on time buffering stored in the memory and executable on the processor. When the dual-objective resource-constrained project scheduling program based on time buffering is executed by the processor, the steps of the dual-objective resource-constrained project scheduling method based on time buffering as described in any one of claims 1 to 7 are implemented.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a dual-objective resource-constrained project scheduling program based on time buffer or a dual-objective resource-constrained project scheduling strategy design program based on time buffer. When the dual-objective resource-constrained project scheduling program based on time buffer is executed by a processor, the steps of the dual-objective resource-constrained project scheduling method based on time buffer as described in any one of claims 1-7 are implemented.

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