Inventory emergency management method and device, computer storage medium and terminal

Abstract

The invention discloses an inventory emergency management method and device, a computer storage medium and a terminal.According to the embodiment of the invention, product oil production and marketing constraints and inventory management constraints are determined through product oil management related information such as node supply and demand, channel transportation, node inventory and pipeline correlation; stock emergency management and production and marketing are coupled into a product oil logistics daytime scheduling model, and product oil logistics plans and stock emergency management requirements are considered at the same time, so that a refinery delivery execution plan, an oil depot goods requiring execution plan, an oil product logistics plan, a pipeline scheduling plan and a node stock plan which meet various constraint conditions can be obtained; the utilization rate of oil demand prediction is effectively improved, the oil depot inventory level is guaranteed, the purposes of economy and practicability of the product oil logistics plan are achieved, and the product oil inventory emergency management efficiency is improved.

Description

Technical Field

[0001] The present application relates to, but is not limited to, finished oil inventory management technology, and particularly to an inventory emergency management method, device, computer storage medium and terminal. Background Art

[0002] Finished oil is an important commodity and strategic material related to the national economy and people's livelihood. Finished oil inventory is an important measure to ensure the supply of finished oil market and stabilize the market price of finished oil. The relevant technology generally optimizes the emergency management of finished oil inventory with the goal of minimum economic efficiency under the premise of meeting basic needs. Since it is based on the situation of relatively stable market demand, when this method only considers economic purposes, the finished oil inventory is often in a low-level operation state. Therefore, once there is a large market fluctuation or other temporary demand, it will lead to an emergency of finished oil inventory, which will further aggravate market fluctuations and make the emergency management efficiency of finished oil inventory low. In addition, due to the large geographical and spatial differences in the supply and demand of finished oil resources, it is more challenging to adjust the node reserve plan in a short period of time. In addition, since the oil depot inventory plan is also strongly coupled with the refinery production plan and transportation plan, one hair can move the whole body; therefore, while paying attention to the needs of inventory emergency management, it is also necessary to pay attention to finished oil production and logistics transportation.

[0003] For refined oil logistics transportation, mathematical programming is the main technology used in related technologies. By inputting the refinery delivery plan, oil depot demand plan and transportation channel plan, and using conventional algorithms to solve the pre-built refined oil logistics optimization mathematical model, a monthly refined oil logistics plan can be obtained. Although the refined oil logistics optimization mathematical model of related technologies is also under continuous development, for example, the transportation process is taken into consideration, such as the multi-mode shipping capacity of the shipping point, the multi-mode receiving capacity of the receiving point, and the single-channel transportation capacity, there is still a certain distance compared to the actual business operation of the project. For example, the refined oil logistics optimization mathematical model, when conducting emergency management of refined oil inventory, only takes into account the upper and lower limits of inventory, that is, at the time node set by the model, the inventory level meets the safety requirements of refined oil storage tanks. However, this method, on the one hand, the calculation time nodes of the model are the beginning and end of the month, and the full span of the time nodes is more than 700 hours, which makes it impossible to track inventory, and the inventory limit constraint itself is of little significance; on the other hand, for the model with subdivided time node classes, although it is possible to track inventory changes (the thickness of the time span is positively correlated with the thickness of inventory tracking), the inventory volume is only determined by the model with economy as the goal, which cannot meet the needs of inventory emergency management, is prone to plan collapse, and has poor executability.

[0004] In summary, how to improve the efficiency of emergency management of refined oil inventory has become a problem to be solved. Summary of the invention

[0005] The following is a summary of the subject matter described in detail in this application. This summary is not intended to limit the scope of the claims.

[0006] The embodiments of the present disclosure provide a method, device, computer storage medium and terminal for emergency management of inventory, which can improve the efficiency of emergency management of finished oil inventory.

[0007] The embodiment of the present disclosure provides a method for inventory emergency management, which is applied to finished oil inventory management, including:

[0008] Determine the production and sales constraints and inventory management constraints of refined oil products based on the refined oil product management related information of the refinery. The refined oil product management related information includes: production operation parameters, oil depot operation parameters, transportation parameters of transportation channels, node reserve oil plan information and inventory emergency plan information;

[0009] According to the production operation parameters, oil depot operation parameters and transportation parameters in the refined oil management related information, the production and sales constraints and inventory management constraints of refined oil, the oil depot reserve constraints and inventory emergency plan information, and the pre-set objective function, the refined oil logistics daytime scheduling model is constructed;

[0010] Based on the predetermined initial plan information of finished oil production and sales and the initial plan information of finished oil inventory, the constructed finished oil logistics daily scheduling model is solved to obtain the finished oil production and sales target plan information and the finished oil inventory target plan information.

[0011] On the other hand, an embodiment of the present disclosure further provides a computer storage medium, in which a computer program is stored. When the computer program is executed by a processor, the above-mentioned inventory emergency management method is implemented.

[0012] In another aspect, an embodiment of the present disclosure further provides a terminal, comprising: a memory and a processor, wherein the memory stores a computer program; wherein:

[0013] The processor is configured to execute the computer program in the memory;

[0014] When the computer program is executed by the processor, the method for emergency inventory management as described above is implemented.

[0015] In another aspect, the embodiment of the present disclosure further provides an apparatus for emergency inventory management, comprising: a constraint determination unit, a model building unit and a processing unit; wherein:

[0016] The constraint unit is set to: determine the production and sales constraints and inventory management constraints of finished oil according to the refined oil management related information of the refinery. The refined oil management related information includes: production operation parameters, oil depot operation parameters, transportation parameters of transportation channels, node reserve plan information and inventory emergency plan information;

[0017] The model building unit is set as follows: according to the production operation parameters, oil depot operation parameters and transportation parameters in the relevant information of finished oil management, the production and sales constraints and inventory management constraints of finished oil, the oil depot reserve constraints and inventory emergency plan information, and the pre-set objective function, the finished oil logistics daytime scheduling model is built;

[0018] The processing unit is set as follows: based on the predetermined finished oil production and sales initial plan information and finished oil inventory initial plan information, the constructed finished oil logistics daily scheduling model is solved to obtain the finished oil production and sales target plan information and the finished oil inventory target plan information.

[0019] Compared with the related art, the present application is applied to finished oil inventory management, including: determining finished oil production and sales constraints and inventory management constraints based on the refined oil management related information of the refinery, the refined oil management related information including: production operation parameters, oil depot operation parameters, transportation parameters of the transportation channel, node oil reserve plan information and inventory emergency plan information; constructing a finished oil logistics daytime scheduling model based on the production operation parameters, oil depot operation parameters and transportation parameters in the refined oil management related information, the determined finished oil production and sales constraints and inventory management constraints, oil depot oil reserve constraints and inventory emergency plan information, and a pre-set objective function; solving the constructed finished oil logistics daytime scheduling model based on the pre-determined finished oil production and sales initial plan information and finished oil inventory initial plan information, and obtaining finished oil production and sales target plan information and finished oil inventory target plan information. The disclosed embodiment determines the production and sales constraints and inventory management constraints of finished oil products through node supply and demand, channel transportation, node inventory and pipeline-related information related to finished oil management, couples inventory emergency management and production and sales to the finished oil logistics daily scheduling model, and considers the finished oil logistics plan and inventory emergency management needs at the same time, so as to obtain the refinery delivery execution plan, oil depot demand execution plan, oil product logistics plan, pipeline scheduling plan and node inventory plan that meet various constraints, effectively improve the utilization rate of oil product demand forecasting, ensure the inventory level of oil depots, achieve the purpose of economic and practicality of finished oil logistics plan, and improve the efficiency of finished oil inventory emergency management. .

[0020] Other features and advantages of the present application will be described in the following description, and partly become apparent from the description, or be understood by implementing the present application. Other advantages of the present application can be realized and obtained by the schemes described in the description and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The accompanying drawings are used to provide an understanding of the technical solution of the present application and constitute a part of the specification. Together with the embodiments of the present application, they are used to explain the technical solution of the present application and do not constitute a limitation on the technical solution of the present application.

[0022] Figure 1 A flowchart of a method for emergency inventory management according to an embodiment of the present disclosure;

[0023] Figure 2 It is a structural block diagram of the device for emergency inventory management according to an embodiment of the present disclosure;

[0024] Figure 3 is a structural block diagram of a terminal according to an embodiment of the present disclosure;

[0025] Figure 4 This is a flowchart of a method for emergency management of refined oil inventory according to an embodiment of the present disclosure;

[0026] Figure 5 A schematic diagram of a refined oil inventory emergency management network according to an embodiment of the present disclosure;

[0027] Figure 6a It is a schematic diagram of the inventory of a refinery within a cycle in the basic example of the embodiment of the present disclosure;

[0028] Figure 6b It is a schematic diagram of the inventory of a refinery within a cycle in Example 1 of the embodiment of the present disclosure;

[0029] Figure 6c It is a schematic diagram of the inventory of a refinery within a cycle in Example 2 of the embodiment of the present disclosure;

[0030] Figure 7a It is a schematic diagram of the inventory of a refinery within a cycle in the basic example of the embodiment of the present disclosure;

[0031] Figure 7b It is a schematic diagram of the inventory of a refinery within a cycle in Example 2 of the embodiment of the present disclosure;

[0032] Figure 8a It is a schematic diagram of the inventory of the oil depot within a period in the basic calculation example of the embodiment of the present disclosure;

[0033] Figure 8b It is a schematic diagram of the inventory of the oil depot within a cycle in Example 2 of the embodiment of the present disclosure. DETAILED DESCRIPTION

[0034] The present application describes multiple embodiments, but the description is exemplary rather than restrictive, and it is obvious to those skilled in the art that there may be more embodiments and implementations within the scope of the embodiments described in the present application. Although many possible feature combinations are shown in the drawings and discussed in the specific embodiments, many other combinations of the disclosed features are also possible. Unless specifically limited, any feature or element of any embodiment may be used in combination with any other feature or element in any other embodiment, or may replace any other feature or element in any other embodiment.

[0035] The present application includes and contemplates combinations of features and elements known to those of ordinary skill in the art. The embodiments, features and elements disclosed in the present application may also be combined with any conventional features or elements to form a unique invention scheme defined by the claims. Any features or elements of any embodiment may also be combined with features or elements from other invention schemes to form another unique invention scheme defined by the claims. Therefore, it should be understood that any feature shown and / or discussed in the present application may be implemented individually or in any appropriate combination. Therefore, except for the limitations made according to the attached claims and their equivalents, the embodiments are not subject to other restrictions. In addition, various modifications and changes may be made within the scope of protection of the attached claims.

[0036] In addition, when describing representative embodiments, the specification may have presented the method and / or process as a specific sequence of steps. However, to the extent that the method or process does not rely on the specific order of the steps described herein, the method or process should not be limited to the steps of the specific order described. As will be understood by those of ordinary skill in the art, other sequences of steps are also possible. Therefore, the specific sequence of the steps set forth in the specification should not be interpreted as a limitation to the claims. In addition, the claims for the method and / or process should not be limited to the steps of performing them in the order written, and those skilled in the art can easily understand that these sequences can be changed and still remain within the spirit and scope of the embodiments of the present application.

[0037] Figure 1 The flowchart of the method for inventory emergency management according to the embodiment of the present disclosure is applied to the inventory management of refined oil products, such as Figure 1 As shown, including:

[0038] Step 101: Determine the production and sales constraints and inventory management constraints of refined oil products according to the refined oil product management related information of the refinery; the refined oil product management related information includes: production operation parameters, oil depot operation parameters, transportation parameters of transportation channels, node reserve oil plan information and inventory emergency plan information;

[0039] Step 102, constructing a daily scheduling model for refined oil logistics based on production operation parameters, oil depot operation parameters and transportation parameters in the refined oil management related information, determined refined oil production and sales constraints and inventory management constraints, oil depot reserve constraints and inventory emergency plan information, and a pre-set objective function;

[0040] Step 103: Based on the predetermined initial plan information of finished oil production and sales and the initial plan information of finished oil inventory, the constructed daily scheduling model of finished oil logistics is solved to obtain the target plan information of finished oil production and sales and the target plan information of finished oil inventory.

[0041] The disclosed embodiment determines the production and sales constraints and inventory management constraints of refined oil products through node supply and demand, channel transportation, node inventory, pipeline-related and other refined oil management-related information, couples inventory emergency management and production and sales to the refined oil logistics daily scheduling model, and takes into account the refined oil logistics plan and inventory emergency management needs at the same time, so as to obtain the refinery delivery execution plan, oil depot demand execution plan, oil product logistics plan, pipeline scheduling plan and node inventory plan that meet various constraints, effectively improves the utilization rate of oil product demand forecasting, ensures the inventory level of oil depots, achieves the goals of economy and practicality of refined oil logistics planning, and improves the efficiency of refined oil inventory emergency management.

[0042] In an exemplary embodiment, step 101 of the disclosed embodiment determines the production and sales constraints of refined oil products according to the refined oil product management related information of the refinery, which may include:

[0043] The production and marketing constraints of refined oil are determined based on the production and operation parameters of the refinery, the operation parameters of the oil depot and the transportation parameters of the transportation channel; among them, the production and marketing constraints of refined oil include: node supply and demand constraints, node production and marketing constraints, channel transportation constraints, pipeline-related constraints and associated constraints.

[0044] In an exemplary embodiment, the inventory management constraints in the embodiment of the present disclosure include: oil reserve constraints and inventory emergency constraints; in the embodiment of the present disclosure, step 101 determines the inventory management constraints based on the refined oil management related information of the refinery, which may include:

[0045] Determine the oil reserve constraints of the oil depot based on the oil depot operation parameters and node reserve plan information;

[0046] Based on the oil depot operation parameters and inventory contingency plan information, inventory contingency constraints are determined.

[0047] In an exemplary instance, the initial planning information for production and sales of refined oil in step 103 of the embodiment of the present disclosure includes: refinery pre-delivery plan, oil depot pre-order plan and transportation channel plan; the initial planning information for refined oil inventory includes: node reserve oil plan information and inventory emergency plan information.

[0048] The information on the initial plan for production and sales of refined oil in the embodiment of the present disclosure can be obtained from the operation system in the relevant technology; the information on the initial plan for production and sales of refined oil is a pre-plan, which refers to the pre-delivery plan submitted by the refinery and the pre-order plan submitted by the oil depot before the transportation channel (logistics) plan is formulated, and fluctuations are usually allowed within the corresponding prescribed range; among them, the pre-delivery plan refers to the plan for the daily production of various oil products by the refinery within a set period; the pre-order plan refers to the plan for the daily demand for various oil products by the oil depot within the period; the transportation channel plan refers to the channel that can be used for oil transportation within the period, including information such as the shipping point, the collection point, the transportation capacity and the time in transit; the period of the information on the initial plan for production and sales of refined oil in the embodiment of the present disclosure may include but is not limited to days, weeks, ten days, months, etc.

[0049] In an exemplary embodiment, the production operation parameters in step 101 of the embodiment of the present disclosure include but are not limited to: maximum delivery capacity, storage capacity lower limit, storage capacity upper limit, delivery volume, production volume and initial inventory; the oil depot operation parameters in the embodiment of the present disclosure include but are not limited to: oil depot receipt volume, oil depot shipping volume, oil depot shortage, market demand, maximum delivery capacity, oil receiving capacity upper limit, storage capacity lower limit, storage capacity upper limit and inventory; the transportation parameters in the embodiment of the present disclosure include but are not limited to: transportation mode, pipeline transportation, non-pipeline transportation, transportation capacity, in-transit time and pipeline status. All constraints included in the production and sales constraints of refined oil are related to one or more parameters of production operation parameters, oil depot operation parameters and transportation parameters of transportation channels.

[0050] In this embodiment, the nodes include refineries and oil depots. The refined oil production and marketing constraints include one or any combination of the following: node supply and demand constraints, node production and marketing constraints, channel transportation constraints, pipeline-related constraints, and associated constraints; each of the above refined oil production and marketing constraints is briefly described below.

[0051] The node supply and demand constraints in the embodiment of the present disclosure may be for oil depots, and must satisfy: within the unit time (cycle) span of the oil depot, the shipment volume to the local market plus the shortage volume should be equal to the demand volume of the local market within the unit time span; the node supply and demand constraints in the embodiment of the present disclosure may satisfy the following formula:

[0052]

[0053] In the formula, represents the amount of oil product o shipped by oil depot j to the local market within time window t, in cubic meters; D t,j,o It represents the demand for oil product o in the local market where oil depot j is located within the time window t, in units of square; O is the set of oil products; J is the set of oil depots.

[0054] The channel transportation constraints in the embodiments of the present disclosure may include: output channel transportation constraints and receiving channel transportation constraints, wherein the output channel transportation constraints may satisfy: the amount of oil products sent out by a refinery or oil depot through a preset transportation method in a unit time should be less than the upper limit of the oil sending capacity of the preset method, and the expression is as follows:

[0055]

[0056] In the formula, It represents the maximum delivery capacity of refinery i or oil depot j through mode n, in cubic meters; I is the set of refineries.

[0057] The transport constraint of the receiving channel can be satisfied as follows: the amount of oil received by a certain oil depot through a preset transportation method per unit time should be less than the upper limit of the oil receiving capacity of the preset method. The expression is as follows:

[0058]

[0059] In the formula, represents the maximum receiving capacity of tank depot j' through mode n, square; Represents the set of refineries that can deliver oil to oil depot j'.

[0060] The node production and sales constraint in the embodiment of the present disclosure may be that the inventory of the oil depot or refinery should always be within its safety inventory range, and the expression is as follows:

[0061]

[0062]

[0063] In the formula, or It represents the lower and upper limits of the storage capacity of oil product o in refinery i and the lower and upper limits of the storage capacity of oil product o in oil depot j, in square meters; T is the time window set.

[0064] In the disclosed embodiment, the refinery inventory is related to the refinery's shipment volume to each oil depot (including pipeline injection volume), its own production volume, and initial inventory, and is expressed as follows:

[0065]

[0066] In the embodiment of the present disclosure, the oil depot inventory is related to the oil depot receiving volume (including pipeline download volume), the shipping volume (transit oil depot), and the initial inventory volume, and the expression is as follows:

[0067]

[0068]

[0069] In the formula, It represents the amount of oil product o injected into the pipeline by refinery (first station) i within the time window t, square; represents the production of oil product o of refinery i within time window t, square; Δt i,j,n / Δt j',j,n It indicates the time limit for transportation from refinery i or oil depot j' to oil depot j by mode n, the number of time windows (can be days); It represents the amount of oil product o downloaded from refinery (first station) i by oil depot (distribution station) j in time window t, square; Represents the set of upstream refineries (first stations) of oil depot (pipeline depot, distribution station) j.

[0070] The pipeline-related constraints in the embodiments of the present disclosure include, but are not limited to, one or any combination of the following: oil batch constraints in the pipeline, backflow constraints, injection / download flow constraints, pipe section flow constraints, injection flow constraints, and injection and distribution constraints.

[0071] in,

[0072] The constraint of the oil batch in the pipeline is: the oil head movement of the oil batch in the pipeline per unit time is consistent with the download amount of the previous oil batch in the pipeline by all sub-transmission stations, that is, the oil head movement of the oil batch b in the pipeline in the time period t~t+1 should be consistent with the download amount of the previous batch b′<b by all sub-transmission stations. The expression is as follows:

[0073]

[0074] In the formula, represents the position coordinates of the oil head of batch b injected by the first station i at time t, in square meters; It represents the volume of batch b' oil product o downloaded from the first station i by the distribution station j within the time window t, in cubic meters.

[0075] In the embodiment of the present disclosure, at the initial moment, the position coordinates of the oil batch in the pipeline are known, and the expression is as follows:

[0076]

[0077] The volume of the uninjected batch is determined by the model and is expressed as follows:

[0078]

[0079] In the formula, It represents the position coordinates of the oil batch b in the pipeline of the first station i, square; It represents the volume of oil product o of batch b injected from the first station i within the time window t, square; They respectively represent the set of oil product batches in the pipeline to which the first station i belongs (one more than the number of batches, indicating that the oil tail position of the batch is also known) and the set of newly injected batches.

[0080] In the embodiment of the present disclosure, the backflow constraint is that the oil batch in the pipeline cannot flow back over time, that is, for the oil batch b in the pipeline, backflow is not allowed to occur over time, and the constraint satisfies the following formula:

[0081]

[0082]

[0083] In the embodiment of the present disclosure, in order to ensure the safe operation of the injection station / distribution station when injecting / unloading oil products, when formulating the scheduling plan, it is necessary to consider the effective working range of the flowmeter, regulating valve and other equipment of the injection station / distribution station and the restrictions of the oil tank on the outflow / inflow flow. Therefore, the injection / unloading flow of the injection station / distribution station cannot exceed the flow limit range, forming an injection / unloading flow constraint, which is expressed as follows:

[0084]

[0085]

[0086] In the formula, represents the upper limit of the injection flow of the first station i, square meters / hour; τ represents the time window span, hours; Y i,b,o is a binary variable, indicating whether the batch b injected at the first station i is oil product o. If the batch b injected at the first station i is oil product o, Y i,b,o =1, the batch b injected at the first station i is not oil product o, Y i,b,o =0; It indicates the upper limit of the download flow rate of the distribution station j along the pipeline to which the first station i belongs, in cubic meters per hour.

[0087] In the embodiment of the present disclosure, for the flow constraint of the pipeline section, at any time, the flow of the pipeline section should be consistent with the total download volume of the downstream distribution station, as shown in the following formula:

[0088]

[0089] In the formula, It indicates the upper limit of the outbound flow rate of the pipeline distribution station j to which the first station i belongs, in cubic meters per hour.

[0090] In the same time window, the injected traffic is equal to the downloaded traffic, forming an injected traffic constraint, which is expressed as follows:

[0091]

[0092] In the embodiment of the present disclosure, the injection and distribution constraints are that the first station or distribution station can perform corresponding operations on the batch of oil products if and only if the batch belongs to the batch that is passing through the station. The judgment condition is that at the start time of the time window, the oil tail of the batch of oil products has not passed this station, and the expression is as follows:

[0093]

[0094] At the end of the time window, the oil head of the batch of oil has passed the station, and the expression is as follows:

[0095]

[0096] Therefore, the constraint expression is as follows:

[0097]

[0098]

[0099] In the formula, z i represents the volume coordinate of the first station i (usually 0), in cubic meters; It is a binary variable, indicating whether the first station i can inject batch b within the time window t. The first station i can inject batch b within the time window t. The first station i cannot perform injection operation on batch b within time window t. M represents a maximum value.

[0100] In this embodiment, the judgment condition is the same as the injection judgment, and the expression is as follows:

[0101]

[0102]

[0103]

[0104]

[0105] In the formula, z i,j It represents the station volume coordinates of pipeline distribution station j to which distribution station i belongs, in units of square meters; is a binary variable, indicating whether the pipeline distribution station j to which the first station i belongs can download batch b within the time window t. The pipeline distribution station j to which the first station i belongs can download batch b within the time window t. Within time window t, the pipeline distribution station j belonging to the first station i cannot download batch b.

[0106] The associated constraints in the embodiment of the present disclosure may be that the injection volume at the first station should be consistent with the volume shipped by the refinery through the pipeline, and the time should correspond, which may include the following constraints:

[0107]

[0108] The amount downloaded by the pipeline distribution station should be consistent with the amount received by the oil depot through the pipeline, and the time should correspond. The following constraints can be included:

[0109]

[0110] The finished oil inventory initial planning information in the embodiment of the present disclosure may include: node oil reserve planning information and inventory emergency planning information;

[0111] In an exemplary embodiment, the node oil reserve plan information in the embodiment of the present disclosure may be in units of cycles, and the inventory emergency plan information may be in units of a certain day or days within the cycle of the node oil reserve plan information. The node oil reserve plan information may be the inventory level that various oil products in a refinery or oil depot need to reach respectively within a longer period of time; the inventory emergency plan information may be the inventory level that a certain oil product in a refinery or oil depot needs to reach within a shorter period of time (even a certain day). Table 1 is an example of node oil reserve plan information and inventory emergency plan information.

[0112] node Oil Inventory planning time Planned inventory (tons) Plan Type R1001 92# Gasoline Full month 1000 Fuel reserve plan D2006 95# Gasoline Day 10 2000 Contingency Planning

[0113] Table 1

[0114] The oil reserve constraint of the oil depot in the embodiment of the present disclosure corresponds to the oil reserve plan. In the embodiment of the present disclosure, for the oil depot, based on historical operating experience or prediction, the inventory level required for each oil product in the next cycle for a long period of time can be obtained. Therefore, the following formula is used to make the inventory meet the requirements:

[0115]

[0116] In the formula, I represents the required inventory of oil product o at node i at time t, in units of cubic meters; RES Represents the set of nodes with oil reserve plan; i RES Represents the set of oil products o involved in the oil reserve plan of node i.

[0117] The inventory emergency constraint in the embodiment of the present disclosure corresponds to the emergency plan. The inventory emergency plan information is a temporary inventory level requirement and has a large volatility. Similar to the oil reserve constraint of the oil depot, the main difference is that the time span is small and the randomness is strong. The expression of the inventory emergency constraint is as follows:

[0118]

[0119] In the formula, I represents the emergency inventory required for oil product o at node i at time t. CON Represents a set of nodes with inventory emergency plan information; T i CON represents the set of time nodes t involved in the inventory emergency plan information of node i; i CON Represents the set of oil products o involved in the inventory emergency plan information of node i.

[0120] In an exemplary embodiment, the embodiment of the present disclosure may construct a daily scheduling model for refined oil logistics based on a neural network algorithm or a deep learning method in the relevant technology;

[0121] After considering constraints such as node supply and demand, channel transportation, node inventory and pipeline-related constraints, the disclosed embodiment takes into account multimodal transport modes, establishes a daily scheduling model for refined oil logistics, realizes inventory tracking functions while formulating logistics plans, and provides an interface for inventory emergency management.

[0122] In an exemplary embodiment, in the embodiment of the present disclosure, the objective function is a function that minimizes the total cost of finished oil logistics and emergency management, and the expression is as follows:

[0123] f=min(f1+f2+f3+f4)

[0124] In the formula, f1 is the refinery logistics fee, f2 is the transit oil depot logistics fee, f3 is the inventory management fee, and f4 is the out-of-stock penalty fee.

[0125] In the embodiment of the present disclosure, the refinery logistics fee includes but is not limited to: the transportation fee incurred by the refinery when shipping to its oil depot through non-pipeline means, and the pipeline transportation fee incurred by the refinery when shipping to its oil depot through pipeline means. In the embodiment of the present disclosure, the refinery logistics fee can be calculated using the following formula:

[0126]

[0127] In the formula, It represents the unit freight cost of oil product o shipped by refinery i to oil depot j by mode n, in yuan / cubic meter;

[0128] It represents the quantity of oil product o delivered by refinery i to oil depot j by mode n in time window (period) t, in cubic meters;

[0129] It indicates the unit pipeline transportation fee for transporting oil product o from the first station (refinery) i to the distribution station (oil depot) j, in yuan / cubic meter;

[0130] It indicates the amount of oil product o downloaded from refinery (first station) i by oil depot (distribution station) j in time window t, in units of cubic meters;

[0131] represents the set of tank depots that can receive oil from tank depot j (not pipeline); Represents the set of oil depots that can receive oil from refinery i (pipeline).

[0132] In the embodiment of the present disclosure, the logistics fee of the transit oil depot includes the secondary transportation fee (without pipeline) between all oil depots, which can be expressed by the following formula:

[0133]

[0134] In the formula, It represents the unit freight of oil product o shipped by oil depot j to oil depot j' by mode n, in Yuan / cubic meter; It indicates the amount of oil product o sent from tank depot j (transit tank depot) to tank depot j' via mode n in time window t, in cubic meters.

[0135] In the embodiment of the present disclosure, the inventory management fee includes the fees incurred by all refineries and oil depots for storing oil products within the time window (period), and the expression is as shown in the following formula:

[0136]

[0137] In the formula, It represents the unit inventory cost of oil product o by refinery i or oil depot j in each time window, in yuan / cubic meter; It represents the inventory of oil product o at refinery i or oil depot j at time t, in cubic meters.

[0138] In the disclosed embodiment, the purpose of setting a shortage penalty fee is to allow shortages to occur in the oil depot, so as to improve the versatility of the model and promote the balance of supply and demand as soon as possible. The expression is shown in the following formula:

[0139]

[0140] In the formula, It represents the unit shortage penalty fee of oil depot j for oil product o, in yuan / cubic meter; It represents the shortage of oil product o in oil depot j within time window t, in cubic meters.

[0141] In an exemplary embodiment, the target plan information of finished oil production and sales in the embodiment of the present disclosure may include: refinery delivery execution plan, oil depot demand execution plan, oil product logistics plan, pipeline scheduling plan, and the target plan information of finished oil inventory includes node inventory plan, etc.; wherein,

[0142] The refinery delivery execution plan and the oil product demand execution plan refer to the executable plans obtained after solving the mathematical model (the finished oil logistics daily scheduling model) and excluding the impact of oil product shortages. The execution plan may have slight differences from the pre-plan;

[0143] The oil product logistics plan refers to the transportation of various oil products between refineries and oil depots. The pipeline scheduling plan refers to the batch movement, injection at injection stations, and distribution at distribution stations of the pipeline involved in the logistics system during the solution cycle. The node inventory plan refers to the node inventory level including the oil reserve plan and emergency plan.

[0144] In an exemplary instance, the embodiment of the present disclosure solves the constructed daily scheduling model of refined oil logistics based on the Gurobi solver (a new generation of large-scale mathematical programming optimizer) to obtain refined oil production and sales target planning information and refined oil inventory target planning information.

[0145] Figure 2 The structure diagram of the device for emergency inventory management according to the embodiment of the present disclosure is as follows: Figure 2 As shown, it includes: a constraint determination unit, a model building unit and a processing unit; wherein,

[0146] The constraint unit is set to: determine the production and sales constraints and inventory management constraints of finished oil according to the refined oil management related information of the refinery. The refined oil management related information includes: production operation parameters, oil depot operation parameters, transportation parameters of transportation channels, node reserve oil plan information and inventory emergency plan information;

[0147] The model building unit is set as follows: according to the production operation parameters, oil depot operation parameters and transportation parameters in the relevant information of finished oil management, the production and sales constraints and inventory management constraints of finished oil, the oil depot reserve constraints and inventory emergency plan information, and the pre-set objective function, the finished oil logistics daytime scheduling model is built;

[0148] The processing unit is set as follows: based on the predetermined finished oil production and sales initial plan information and finished oil inventory initial plan information, the constructed finished oil logistics daily scheduling model is solved to obtain the finished oil production and sales target plan information and the finished oil inventory target plan information.

[0149] The disclosed embodiment determines the production and sales constraints and inventory management constraints of refined oil products through node supply and demand, channel transportation, node inventory, pipeline-related and other refined oil management-related information, couples inventory emergency management and production and sales to the refined oil logistics daily scheduling model, and takes into account the refined oil logistics plan and inventory emergency management needs at the same time, so as to obtain the refinery delivery execution plan, oil depot demand execution plan, oil product logistics plan, pipeline scheduling plan and node inventory plan that meet various constraints, effectively improves the utilization rate of oil product demand forecasting, ensures the inventory level of oil depots, achieves the goals of economy and practicality of refined oil logistics planning, and improves the efficiency of refined oil inventory emergency management.

[0150] See also Figure 3 The embodiment of the present disclosure also provides a terminal, including a memory 101 (such as a non-volatile memory), a processor 102, and a computer program stored in the memory 101 and executable on the processor 102. When the processor 102 executes the program, it implements any possible steps of the above-mentioned method for implementing the above-mentioned inventory emergency management, which can be equivalent to the above-mentioned inventory emergency management device. Of course, the processor can also be used to process other data or operations. The electronic device can be a PC, a server, a terminal, and other devices. Figure 3 As shown, the terminal may also generally include: a memory 103, a network interface 104, and an internal bus 105. In addition to these components, other hardware may also be included, which will not be described in detail.

[0151] The embodiment of the present disclosure also provides a computer storage medium, in which a computer program is stored. When the computer program is executed by a processor, the above-mentioned inventory emergency management method is implemented.

[0152] The embodiment of the present disclosure also provides a terminal, including: a memory and a processor, wherein a computer program is stored in the memory;

[0153] in,

[0154] The processor is configured to execute the computer program in the memory;

[0155] When the computer program is executed by a processor, the above-mentioned method of inventory emergency management is implemented.

[0156] The following briefly describes the embodiments of the present disclosure through application examples. The application examples are only used to illustrate the embodiments of the present disclosure and are not used to limit the protection scope of the embodiments of the present disclosure.

[0157] Application Examples

[0158] Figure 4 For the embodiment of the present disclosure, a flowchart of the method for emergency management of finished oil inventory is shown as follows: Figure 4As shown, the input parameters include two parts. The first part of the input parameters includes: refinery pre-delivery plan, oil depot pre-order plan and transportation channel plan; the second part of the input parameters includes: node oil reserve plan information and inventory emergency plan information; wherein, the first part of the input parameters and the second part of the input parameters are input into the finished oil logistics daily scheduling model, and the constructed node supply and demand constraints, node production and sales constraints, channel transportation constraints, pipeline related constraints, association constraints, oil depot oil reserve constraints and inventory emergency constraints are used to constrain the finished oil logistics daily scheduling model, so as to output the finished oil production and sales target plan information and the finished oil inventory target plan information through the constrained finished oil logistics daily scheduling model, wherein the finished oil production and sales target plan information includes: refinery delivery execution plan, oil depot order execution plan, oil product logistics plan, pipeline scheduling plan, and the finished oil inventory target plan information includes the node inventory plan.

[0159] Figure 5 Schematic diagram of the finished oil inventory emergency management network according to the embodiment of the present disclosure, as shown in Figure 5 As shown, in the finished oil emergency management network, there are 8 refineries numbered R1 to R8, 19 oil depots numbered D1 to D19, and 1 finished oil pipeline; the starting point of the finished oil pipeline is R4, the end point is D19, and there is an intermediate injection station (refinery) R7. The entire pipeline line is equipped with 8 distribution stations (D11, D13, D14-D19) including the terminal station; it is assumed that the finished oil emergency management transports a total of 5 kinds of oil products, namely 0# diesel, -35# diesel, 92# gasoline, 95# gasoline and 98# gasoline; among them, the R4-D19 pipeline only transports 0# diesel and 92# gasoline.

[0160] The pre-delivery plan for refineries R1 to R8 is shown in Table 2, and the pre-order plan for oil depots D1 to D19 is shown in Table 3. The nodes with no delivery or order plan within this cycle (a total of 28 days) have been omitted in the table.

[0161] Refinery Oil Delivery volume (tons) Refinery Oil Delivery volume (tons) R1 0#Car Diesel 71000 R3 98# Gasoline 700 R1 -35# car diesel 1000 R4 0#Car Diesel 70000 R1 92# Gasoline 38000 R5 0#Car Diesel 113300 R1 95# Gasoline 9000 R5 -35# car diesel 4000 R2 0#Car Diesel 35000 R5 92# Gasoline 41000 R2 -35# car diesel 5000 R5 95# Gasoline 26000 R2 92# Gasoline 20000 R6 92# Gasoline 6700 R2 95# Gasoline 4000 R6 95# Gasoline 5300 R3 0#Car Diesel 91700 R7 0#Car Diesel 25000 R3 92# Gasoline 80000 R8 92# Gasoline 23300 R3 95# Gasoline 14300 R8 95# Gasoline 4700

[0162] Table 2

[0163] Oil depot Oil Quantity required (tons) Oil depot Oil Quantity required (tons) D1 0#Car Diesel 30000 D8 95# Gasoline 12000 D2 0#Car Diesel 10000 D8 98# Gasoline 700 D3 0#Car Diesel 35000 D9 0#Car Diesel 61000 D3 -35# car diesel 1000 D9 -35# car diesel 4000 D3 92# Gasoline 18000 D9 92# Gasoline 22000 D3 95# Gasoline 5000 D9 95# Gasoline 13300 D4 0#Car Diesel 30000 D10 0#Car Diesel 20000 D4 92# Gasoline 20000 D11 0#Car Diesel 45000 D4 95# Gasoline 4000 D11 92# Gasoline 10000 D5 0#Car Diesel 30000 D12 0#Car Diesel 10000 D5 92# Gasoline 25000 D13 95# Gasoline 3000 D5 95# Gasoline 5000 D14 0#Car Diesel 10000 D6 92# Gasoline 20000 D14 92# Gasoline 2000 D6 95# Gasoline 10000 D14 95# Gasoline 1000 D7 0#Car Diesel 35000 D15 0#Car Diesel 15000 D7 -35# car diesel 5000 D15 92# Gasoline 15000 D7 92# Gasoline 20000 D15 95# Gasoline 2000 D7 95# Gasoline 4000 D17 0#Car Diesel 25000 D8 0#Car Diesel 50000 D17 92# Gasoline 13000 D8 92# Gasoline 44000 D17 95# Gasoline 4000

[0164] Table 3

[0165] In the embodiment of the present disclosure, three examples are set, including a basic example, example 1 and example 2, wherein the basic example is an example of the related art that does not consider emergency situations (Table 1 and Table 2), and example 1 only involves the oil reserve plan of one refinery, that is, R4's inventory level of 0# diesel, 92# gasoline and 95# gasoline on any day in this cycle is not less than 1,000 tons; Example 2 is based on example 1, and adds R1's oil reserve plan and D5's emergency plan, wherein D5 requires that the inventory of 95# gasoline on the 10th and 20th days is not less than 500 tons, as shown in Table 4.

[0166]

[0167] Table 4

[0168] In the disclosed embodiment, based on Tables 2 and 3, the parameter values ​​involved in the basic example are input into the refined oil logistics daily scheduling model that does not include inventory management constraints, and based on the Gurobi solver, the refined oil logistics daily scheduling model that does not include inventory management constraints is solved; and based on Tables 2, 3 and 4, the parameter values ​​involved in Examples 1 and 2 are respectively input into the refined oil logistics daily scheduling model, and based on the Gurobi solver, the refined oil logistics daily scheduling model (mathematical model) is solved to obtain the refinery delivery execution plan, the oil depot demand execution plan, the oil product logistics plan, the pipeline scheduling plan and the node inventory plan, and the solution results are mainly used to show the inventory changes (a total of 28 days).

[0169] Taking refinery R4 as an example, Figure 6a It is a schematic diagram of the inventory of a refinery within a cycle in the basic example of the embodiment of the present disclosure; Figure 6b Schematic diagram of the inventory of a refinery in a cycle in Example 1 of the embodiment of the present disclosure, such as Figure 6b As shown, at time nodes 2 to 29, the inventory increased significantly, meeting the oil reserve requirements (≥1,000 tons); Figure 6c Schematic diagram of the inventory of a refinery in a cycle in Example 2 of the embodiment of the present disclosure, such as Figure 6c As shown in the figure, at time nodes 2 to 29, the inventory increased significantly, meeting the oil reserve requirements. Taking refinery R1 as an example, Figure 7a It is a schematic diagram of the inventory of a refinery within a cycle in the basic example of the embodiment of the present disclosure; Figure 7b Schematic diagram of the inventory of a refinery in a cycle in Example 2 of the embodiment of the present disclosure, such as Figure 7b As shown, for the whole month (28 days, time nodes 2 to 29), the reserve of 0# diesel and 92# gasoline meets the requirement of no less than 2,000 tons, the reserve of -35# diesel meets the requirement of no less than 200 tons, and the reserve of 95# gasoline meets the requirement of 500 tons. Taking oil depot D5 as an example, Figure 8a It is a schematic diagram of the inventory of the oil depot within a period in the basic calculation example of the embodiment of the present disclosure; Figure 8b Schematic diagram of the inventory of the oil depot in the cycle in Example 2 of the embodiment of the present disclosure, as shown in FIG. Figure 8b As shown, around time nodes 11 (10th day) and 21 (20th day), the inventory increased significantly, meeting the oil reserve requirements.

[0170] See also Figure 6a-6c , 7a~7b and 8a~8b, compared with the basic examples of related technologies, the results of Examples 1 and 2 meet the requirements of oil reserve or emergency, such as: the inventory level of 0# diesel, 92# gasoline and 95# gasoline of R4 is required to be no less than 1000 tons throughout the month; the inventory level of 0# diesel and 92# gasoline of R1 is required to be no less than 2000 tons, -35# diesel is required to be no less than 200 tons, and 95# gasoline is required to be no less than 500 tons throughout the month; the emergency amount of 95# gasoline of D5 reaches 500 tons on the 10th day (the 11th time node in the figure) and the 20th day (the 21st time node in the figure).

[0171] The disclosed embodiment improves the practicality of logistics planning by taking into account the optimization of refined oil logistics and inventory management. The parameters are input into five parts: the daily scheduling model of refined oil logistics considering multimodal transport, inventory management constraints, and result output. The core part is the daily scheduling model of refined oil logistics considering multimodal transport and inventory management constraints. The output includes refinery delivery execution plan, oil depot demand execution plan, oil product logistics plan, pipeline scheduling plan, and node inventory plan. It can solve the uneconomical phenomenon caused by the long-standing separation of logistics optimization and inventory management and the problem of poor executability of logistics plans, and can effectively meet the oil depot's oil reserve needs and inventory emergency needs. The disclosed embodiment couples inventory management constraints to a daily scheduling model for refined oil logistics that takes multimodal transport into consideration. While optimizing logistics, it collaboratively considers node oil reserve plan information and inventory emergency plan information, which can effectively reduce the degree of manual participation, thereby improving the practicality of logistics planning, reducing the economic expenditure of the logistics system, and improving the efficiency of emergency management. The refined oil inventory emergency management method based on logistics optimization utilizes a daily scheduling model for refined oil logistics that takes multimodal transport into consideration. The model takes the lowest oil product logistics costs, inventory management costs, and out-of-stock penalty costs as its goal, and considers node supply and demand, channel transportation, node inventory, pipeline-related constraints, and inventory management constraints including oil depot oil reserve constraints and emergency constraints. The refined oil inventory emergency management method based on logistics optimization, after inputting the refinery pre-delivery plan, the oil depot pre-order plan, the transportation channel plan, the node oil reserve plan information, and the inventory emergency plan information, can obtain the refinery delivery execution plan, the oil depot order execution plan, the oil product logistics plan, the pipeline scheduling plan, and the node inventory plan that meet the various constraints.

[0172] It will be appreciated by those skilled in the art that all or some of the steps, systems, and functional modules / units in the methods disclosed above may be implemented as software, firmware, hardware, and appropriate combinations thereof. In hardware implementations, the division between the functional modules / units mentioned in the above description does not necessarily correspond to the division of physical components; for example, a physical component may have multiple functions, or a function or step may be performed by several physical components in cooperation. Some or all components may be implemented as software executed by a processor, such as a digital signal processor or a microprocessor, or implemented as hardware, or implemented as an integrated circuit, such as an application-specific integrated circuit. Such software may be distributed on a computer-readable medium, which may include a computer storage medium (or non-transitory medium) and a communication medium (or temporary medium). As known to those skilled in the art, the term computer storage medium includes volatile and non-volatile, removable and non-removable media implemented in any method or technology for storing information (such as computer-readable instructions, data structures, program modules, or other data). Computer storage media include, but are not limited to, RAM, ROM, EEPROM, flash memory or other memory technology, CD-ROM, digital versatile disks (DVD) or other optical disk storage, magnetic cassettes, magnetic tapes, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to store the desired information and can be accessed by a computer. In addition, it is well known to those of ordinary skill in the art that communication media typically contain computer-readable instructions, data structures, program modules, or other data in a modulated data signal such as a carrier wave or other transport mechanism, and may include any information delivery media.

Claims

1. A method for emergency inventory management, applied to finished oil inventory management, characterized in that: include: Determine the production and sales constraints and inventory management constraints of refined oil products based on the refined oil product management related information of the refinery. The refined oil product management related information includes: production operation parameters, oil depot operation parameters, transportation parameters of transportation channels, node reserve oil plan information and inventory emergency plan information; According to the production operation parameters, oil depot operation parameters and transportation parameters in the information related to finished oil management, the production and sales constraints and inventory management constraints of finished oil, the oil depot reserve constraints and inventory emergency plan information, and the pre-set objective function, the finished oil logistics daytime scheduling model is constructed; Based on the predetermined initial plan information of finished oil production and sales and the initial plan information of finished oil inventory, the constructed finished oil logistics daily scheduling model is solved to obtain the finished oil production and sales target plan information and the finished oil inventory target plan information.

2. The method according to claim 1, characterized in that: Determining the production and sales constraints and inventory management constraints of refined oil products based on the refined oil product management related information of the refinery includes: Determine the production and marketing constraints of refined oil according to the production and operation parameters, the oil depot operation parameters and the transportation parameters of the transportation channel in the refined oil management related information, wherein the production and marketing constraints of refined oil include one or any combination of the following: node supply and demand constraints, node production and marketing constraints, channel transportation constraints, pipeline related constraints and associated constraints; The inventory management constraint is determined according to the oil depot operation parameters, the node oil reserve plan information and the inventory emergency plan information in the refined oil management related information.

3. The method according to claim 2, characterized in that The inventory management constraints include: oil depot reserve constraints and inventory emergency constraints. The determination of inventory management constraints includes: Determining the oil reserve constraint of the oil depot based on the oil depot operation parameters and the node oil reserve plan information; The inventory contingency constraint is determined based on the oil depot operation parameter and the inventory contingency plan information.

4. The method according to claim 2, characterized in that: When the refined oil production and sales constraint includes the node supply and demand constraint, the node supply and demand constraint includes: The quantity shipped by the oil depot to the local market within a unit time span plus the shortage quantity is equal to the demand of the local market within that unit time span.

5. The method according to claim 2, characterized in that: When the refined oil production and marketing constraints include the channel transportation constraints, the channel transportation constraints include the output channel transportation constraints and the receiving channel transportation constraints, wherein: The transport constraint of the output channel is: for a refinery or oil depot, the amount of oil products shipped by the preset transport method per unit time should be less than the upper limit of the oil shipping capacity of the preset method; The receiving channel transportation constraint is: for an oil depot, the amount of oil received by it through a preset transportation method per unit time is less than the upper limit of the preset method's oil receiving capacity.

6. The method according to claim 2, characterized in that When the refined oil production and marketing constraint includes the node production and marketing constraint, the node production and marketing constraint includes: The inventory at a tank farm or refinery is always within its corresponding safety stock range.

7. The method according to claim 2, characterized in that: When the refined oil production and marketing constraint includes the associated constraint, the associated constraint includes: The injection volume at the first station should be consistent with the volume shipped by the refinery through pipeline, and the time should correspond; and the download volume at the pipeline distribution station should be consistent with the volume received by the oil depot through pipeline, and the time should correspond.

8. The method for emergency management of finished oil inventory according to claim 2, characterized in that: When the refined oil production and marketing constraints include pipeline-related constraints, the pipeline-related constraints include: Oil batch constraints, backflow constraints, injection / download flow constraints, pipe section flow constraints, injection flow constraints, and injection and distribution constraints in pipelines; Among them, the oil batch constraint in the pipeline is that the oil head movement of the oil batch in the pipeline per unit time is consistent with the download volume of the previous oil batch in the pipeline by all sub-transmission stations; the backflow constraint is that the oil batch in the pipeline does not flow back over time; the injection / download flow constraint is: the injection flow of the injection station is less than or equal to the flow limit range, and the download flow of the sub-transmission station is less than or equal to the flow limit range; the pipe section flow constraint is that at any time, the flow of the pipe section should be consistent with the total download volume of the downstream sub-transmission station; the injection flow constraint is that the injection flow is equal to the download flow; the injection and distribution constraints are that the first station or sub-transmission station can perform corresponding operations on the batch of oil products if and only if the batch belongs to a batch that is passing through the station.

9. The method according to any one of claims 1 to 8, characterized in that: The objective function is the following function that minimizes the total cost of refined oil logistics and emergency management: f=min(f1+f2+f3+f4) In the formula, f1 is the refinery logistics fee, f2 is the transit oil depot logistics fee, f3 is the inventory management fee, and f4 is the out-of-stock penalty fee.

10. A computer storage medium storing a computer program, wherein the computer storage medium stores a computer program, and when the computer program is executed by a processor, the method for emergency inventory management according to any one of claims 1 to 9 is implemented.

11. A terminal, comprising: A memory and a processor, wherein the memory stores a computer program; wherein, The processor is configured to execute the computer program in the memory; When the computer program is executed by the processor, the method for emergency management of inventory according to any one of claims 1 to 9 is implemented.

12. A device for emergency inventory management, comprising: Determine the constraint unit, build the model unit and the processing unit; wherein, The constraint unit is set to: determine the production and sales constraints and inventory management constraints of finished oil according to the refined oil management related information of the refinery. The refined oil management related information includes: production operation parameters, oil depot operation parameters, transportation parameters of transportation channels, node reserve oil plan information and inventory emergency plan information; The model building unit is set as follows: according to the production operation parameters, oil depot operation parameters and transportation parameters in the relevant information of finished oil management, the production and sales constraints and inventory management constraints of finished oil, the oil depot reserve constraints and inventory emergency plan information, and the pre-set objective function, the finished oil logistics daytime scheduling model is built; The processing unit is set as follows: based on the predetermined finished oil production and sales initial plan information and finished oil inventory initial plan information, the constructed finished oil logistics daily scheduling model is solved to obtain the finished oil production and sales target plan information and the finished oil inventory target plan information.

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