Method for initiating the migration of an application over a wireless connection

Abstract

The invention relates to a method (100) for initiating a migration of an application via a wireless connection, wherein a migration management function (10) performs the following steps: - Providing (101) an interface from a device within a wireless, preferably cellular, communication network to a cloud component and / or to a core network component of the wireless communication network, wherein the interface enables the initiation of the migration of the application over the wireless connection; - Receiving (102) information regarding the application in relation to a type and / or condition and / or requirement for the migration of the application; - Receiving (103) network information regarding the wireless connection between the device and the cloud component with respect to at least one wireless connection performance indicator; - Distributing (104) the received application and / or network information to each of the components via the provided interface(s) to enable the migration of the application; - Initiating (105) the migration of the application over the wireless connection based on the distributed information.

Description

[0001] The invention relates to a method for initiating the migration of an application via a wireless connection. Furthermore, the invention relates to a migration management function, a computer program, and a computer-readable storage medium for this purpose. State of the art

[0002] Deploying computing power in the cloud, for example, in a multi-access edge computing (MEC) platform near the network edge or in a data center, is a common solution for offloading computing tasks from an endpoint, thereby saving energy and hardware components. Such computing tasks can be any type of application function running in the cloud environment, such as a microservice, a container, or part of a virtual machine (VM). The application migration process is often treated as normal traffic on a mobile network. A disadvantage is that service classes or certain air interface configurations are not optimized for this traffic. Therefore, the network lacks features for optimizing network operations and performance based on application and context information.Furthermore, such mechanisms may not be optimized for supporting a function offloading process or application migration—that is, for example, transferring a function like an executable file that requires high CPU utilization, along with the application's state under specific time constraints. Application migration has been known and well understood for many years as the process of moving an application from one data center to another or between two compute nodes. Virtual machine (VM) encapsulation is commonly used for security reasons, as well as for isolation between multi-tenant applications in cloud computing. Live migration can be used for VM migration within data centers to minimize application downtime.

[0003] However, no supporting or controlling function exists to migrate or outsource an application to a cellular communication network, especially via a wireless connection, in a timely and reliable manner. The network cannot provide any guarantees for outsourcing performance, nor can information from the outsourcing process be used to optimize the network configuration. Consequently, the migration or outsourcing process is only assigned a best-effort service or, at best, a guaranteed bitrate, which is insufficient for timely and highly reliable application migration in both communication directions. This can adversely affect the timely completion of the migration process and thus delay the availability of the outsourced function in the cloud.Furthermore, a migration that is frequently interrupted or aborted can lead to the unavailability of the outsourced function or to very long application downtimes. Thus, all these effects can adversely affect performance or create a critical hazard situation, such as with outsourced ADAS functions in a vehicle. Disclosure of the invention

[0004] The aforementioned problem is solved by a method with the features of claim 1, a migration management function with the features of claim 11, a computer program with the features of claim 12, and a computer-readable storage medium with the features of claim 13. Further features and details of the invention are disclosed in the respective dependent claims, the description, and the drawings. Features and details described in connection with the method according to the invention also correspond in each case to the computer program, the data processing device, and the computer-readable storage medium according to the invention, and vice versa, so that mutual reference can always be made with regard to the disclosure of the individual aspects of the invention.

[0005] The task is solved in particular by a procedure for initiating an application migration over a wireless connection. A migration management function performs the following steps: - Providing an interface from a device within a wireless, preferably cellular, communication network to a cloud component and / or to a core network component of the wireless communication network, wherein the interface enables the initiation of the migration of the application via the wireless connection; - Receiving information about the application regarding a type and / or state and / or a requirement for application migration; - Receiving network information about the wireless connection between the device within the wireless communication network and the cloud component with regard to at least one performance indicator of the wireless connection; - Distributing the received application and / or network information to each of the components via the provided interfaces to enable application migration; - Initiating the migration of the application over the wireless connection based on the distributed information.

[0006] Application migration can also include or consist of offloading a function over the wireless connection. The application is preferably migrated or offloaded from the device to the cloud component and / or the core network component. This has the advantage that, through close coupling or integration of the migration management function or offloading management instance with the cloud computing components and the components of the wireless communication network, especially the 3GPP core network components, the successful execution of an application migration over a wireless connection is significantly improved. Furthermore, this advantageously enables application migration with regard to timing and reliability. It also helps to avoid or at least minimize application downtime.Furthermore, this has the advantage that the mitigation and / or prevention of adverse situations with regard to outsourcing the function or migrating the application via the wireless connection is ensured, and manual intervention is advantageously reduced by automating the optimization and adaptation process.

[0007] It is possible that the procedure includes the following further step: - Initiate, on the cloud component and / or on the core network component and / or a component of the radio access network of the wireless communication network, an adaptation of a configuration for the migration of the application based on the distributed information, where the initiation is further based on the adapted configuration on the cloud component and / or on the core network component and / or on the radio access network component.

[0008] This enables an improved application migration process based on distributed information received from both the cloud computing and wireless communication network sides. Furthermore, it efficiently ensures the successful completion of the application migration process.

[0009] It is conceivable that the procedure includes the following further step: - Initiate, on the core network component and / or cloud component, an adjustment of the configuration for the migration of the application based on a time model for the application migration, whereby the model provides a dynamic probability estimate of the required migration time, based on an evaluation of the predicted time required for the migration of the application with respect to various environmental influences.

[0010] This enables faster and more accurate estimation of the time required to move an application, in its virtual machine or image, from a device, such as user equipment (UE), to a cloud environment, such as an edge cloud computing component. Utilizing this model has the advantage of predicting migration dynamics, for example, using machine learning, and then sharing this information with the cellular system, such as the wireless communication network, allowing it to adapt as needed. Furthermore, this provides insights into the likelihood of migration and, advantageously, predicts the time required to transfer an application from a device to the cloud or vice versa. Finally, this allows for efficient adjustment of the application migration process.

[0011] It is also possible that the procedure includes the following further step: - Monitoring the migration of the application before and during the migration process based on the distributed information.

[0012] This allows for precise control of the initiated migration. Furthermore, it has the advantage of enabling the migration settings to be adjusted or reconfigured based on information received or used from the various components.

[0013] It is possible that, after initiation, the process includes at least one of the following further steps: - Initiating a migration of an image of a virtual machine and / or a containerized application and / or a microservice from one cloud component to another based on the distributed information; - Initiating an adjustment of at least one control parameter for application migration with respect to memory delta encoding and / or information deduplication and / or data compression to optimize the migration of the application in terms of time and / or reliability and / or availability.

[0014] The use of the migration management function according to the invention enables more efficient communication and / or a more efficient exchange of information between the components involved in the method according to the invention when outsourcing a function via the wireless connection.

[0015] It is also conceivable that the procedure includes the following further step: - Initiating an adaptation for the migration of the application based on a prioritized quality service profile regarding the wireless communication network.

[0016] This has the advantage that the reliability of the application migration process is ensured through the efficient use of the provided network information.

[0017] It is possible that the procedure includes the following further step: - Initiate an adaptation to migrate the application based on the provision of a dedicated network slice to ensure the completion of the application migration.

[0018] This has the advantage that functional outsourcing is significantly ensured through the use of dedicated network resources.

[0019] It is also possible that the procedure includes at least one of the following further steps: - Initiating a determination of the current and / or future location of the device based on location services within the wireless communication network; - Initiating joining and / or leaving a private communication group within the wireless communication network.

[0020] The application is preferably migrated in response to joining and / or leaving the private communications group. The application may also be migrated if the device's current and / or future location is within or outside a defined area.

[0021] This makes it possible to ensure an optimal time for the migration of the application, taking into account the movement of the device, such as user equipment (UE) or a vehicle, within the wireless communication network.

[0022] It is possible that the migration management function includes an application migration monitoring function and / or an application migration control function, with each of the functions configured to monitor and control the migration of the application before and / or during the migration process.

[0023] This function advantageously provides an interface to initiate the exchange of information regarding the application and network, taking into account environmental influences on a wireless connection in a wireless communication network. Furthermore, this enables effective, optimized control, configuration, and / or adaptation of the application migration.

[0024] It is possible for the migration management function to be associated with the device and / or the wireless communication network and / or the cloud component. This advantageously allows for an improved functional outsourcing process based on the type and / or state of the application being migrated.

[0025] In another aspect of the invention, a migration management function can be provided for initiating the migration of an application via a wireless connection, configured to execute the method according to the invention. For example, a computer or a virtual computer can be provided as a function, which executes the computer program according to the invention. The computer can have at least one processor that can be used to execute the computer program. Furthermore, a non-volatile data memory can be provided in which the computer program can be stored and from which the computer program can be read by the processor for execution.

[0026] In another aspect of the invention, a computer program, in particular a computer program product, can be provided, comprising instructions which, when executed by a computer, cause the computer to carry out the method according to the invention. Thus, the computer program according to the invention can have the same advantages that are described in detail with respect to a method according to the invention.

[0027] According to another aspect of the invention, a computer-readable storage medium can be provided which comprises the computer program according to the invention and / or instructions which, when executed by a computer, cause the computer to perform the steps of the method according to the invention. The storage medium can be formed from a data storage device, such as a hard disk, and / or non-volatile memory and / or a memory card and / or a solid-state drive. The storage medium can, for example, be integrated into the computer.

[0028] Furthermore, the method according to the invention can be implemented as a computer-implemented method.

[0029] Further advantages, features, and details of the invention will become apparent from the following description, in which embodiments of the invention are described in detail with reference to the drawings. In this context, the features mentioned in the claims and in the description can be essential to the invention, either individually or in any combination. The following are shown: Fig. 1: a method, computer program, storage medium and a device according to embodiments of the invention, Fig. 2: A schematic overview according to embodiments of the invention.

[0030] The core of the invention lies in coupling and / or integrating one or more offloading management instances with the cellular system. This is intended to enable a functional offloading process under strict timing and reliability requirements. This allows a migration to be completed within a specific timeframe or by a predefined target date.

[0031] Furthermore, this allows for minimizing application downtime. It also ensures the availability of the outsourced function in accordance with the overall system availability requirements for that function and / or minimizes the likelihood of the application migration not being completed on time. Coupling or integration can be achieved through an interface between the outsourcing management instance and corresponding components of the wireless system. For example, an outsourcing management instance could be a hypervisor as part of the MEC platform or the backend server.

[0032] Achieving timing and reliability targets can rely on appropriate information exchange between these components, on the basis of which the overall system can be optimized by configuring the relevant parameters through the outsourcing management instance.

[0033] Based on developments in wireless, preferably cellular, communication networks such as 3GPP communication networks, e.g., a 5G or 6G communication network, the method of the invention can enable greater integration of network connectivity and edge cloud computing. Therefore, once a function or application is operational in the cloud environment, the wireless connection between the (end) device and the function to be outsourced or the application to be migrated can be configured to advantageously meet the migration requirements, e.g., with regard to data rate, latency, or the like.

[0034] Fig. Figure 1 shows a method, a computer program, a storage medium and a station according to embodiments of the invention. Fig. Figure 1 shows a procedure 100 for initiating an application migration over a wireless connection. A migration management function 10 performs the following steps: In step 101, an interface to a cloud component and / or a core network component of a wireless, preferably cellular, communication network is provided. This interface enables the initiation of application migration via the wireless connection. In step 102, information about the application regarding its type, state, and / or migration requirements is received. Subsequently, in step 103, network information about the wireless connection between a device in the wireless communication network and a cloud component is received, specifically regarding at least one wireless connection performance indicator. In step 104, the received application and / or network information is distributed to each component via the provided interfaces to enable and / or optimize the application migration.In step 105, the migration of the application via the wireless connection is initiated based on the distributed information.

[0035] Fig. Figure 1 further shows a migration management function 10, which may include a computer 15 and a computer-readable storage medium 15. The computer-readable storage medium 15 includes a computer program 70.

[0036] Fig. Figure 2 represents a schematic example according to embodiments of the invention.

[0037] Fig. Figure 2 shows the different components that may be involved in the application migration or function outsourcing process. Fig. 2 represents a migration management function 10, a device 20, a cloud computing component 30 with a multi-access edge computing platform (MEC) 31, a 3GPP core network 40 with various network components 41, 42, 43, and a backend data center 50 with a server 51. Furthermore, in Fig. Figure 2 shows a base station 60. The base station 60 can be a radio access network component 60 of a 3GPP radio access network. The in Fig. The multi-access edge computing platform shown in Figure 2 simplifies data processing, analysis, and decision-making at or near the data source, offering benefits such as reduced latency, improved data privacy, and efficient bandwidth utilization. An edge computing platform processes data locally, eliminating the need to send all information to a central server or the cloud. This results in faster data processing and lower latency. Edge platforms help reduce the amount of data that needs to be transferred to the cloud, optimize bandwidth utilization, and lower data transfer costs. Edge computing platforms can be deployed across distributed environments, making them scalable and adaptable to different workloads.

[0038] The in Fig. 2. The 3GPP core network 40 shown, for example, comprises a 5G or 6G core network of a 3GPP network, which has various components or network functions, such as a network exposure function 41 (NEF), an application function 42 (AF), a policy control function 43 (PCF) and / or another suitable existing network function or a new network function in the 3GPP network.

[0039] Fig. Figure 2 further shows a backend data center 50 with one server. A backend data center 50 is a central infrastructure that can house computing, storage, and networking equipment. Its main function is data processing, storage, and management for various applications and services.

[0040] The method according to the invention can provide a migration management function 10 between the in Fig. The components shown (20, 30, 40, and 50) are required. While NEF 41 can provide services for other network functions, such as monitoring network performance, AF 42 may handle more advanced network performance forecasting based on measurement data. Furthermore, PCF 43 can be the component that manages policies for UEs, such as Quality of Service (QoS) profiles.

[0041] Fig. Figure 2 shows the migration management function 10, which may include an application migration monitoring function 11 and / or an application migration control function 12. Each of the functions 11 and 12 is configured to monitor and control the migration of the application before and / or during the migration process. The migration management function 10 can interact and / or communicate with each of the components 30, 40, and 50, as indicated by the bidirectional arrows in Figure 2. Fig. Figure 2 illustrates this. Furthermore, the migration management function 10 can optionally be assigned to the cloud computing component 30 and / or the 3GPP core network component 40 and / or the backend data center 50 and / or a wireless access network component, such as a base station 60 and / or a device 20, for initiating the migration of an application. This is illustrated by the dashed boxes 10', 10" and 10 in Fig. 2 shown. Fig. Figure 2 further illustrates the Application Migration Monitoring Function (AMMF) 11, which can monitor the state, performance, and progress of an application migration process. This function 11 can, for example, be part of the Compute Management Unit (in Fig. 2 (not shown), for example, a hypervisor, but it may also be closely integrated into the 3GPP core and / or access network component 30, 60, or assigned to the AF 42. The latter has the advantage that the computing infrastructure can be located physically or logically close to the wireless communication network. The AMMF 11 can distribute the relevant information for function outsourcing to the components involved in the method according to the invention.

[0042] Furthermore, it shows Fig. 2. An Application Migration Control Function (AMCF) 12, which may be included in the Migration Management Function 10. The AMCF 12 can configure and control the function migration process based on information provided by the AMMF 11, as well as network performance measurements and forecasts from the wireless communication network functions.

[0043] This allows the migration management function 10, for example, to initiate a migration of base virtual machine (VM) images and / or to adjust certain control parameters regarding memory / delta encoding, information deduplication, and data compression to create the image overlays. Furthermore, this ensures that a suitable compromise is found between migration duration (see time constraints), migration success rate (see reliability constraints), and application downtime (see availability constraints). Not in Fig. As shown in Figure 2, the migration management function 10, which includes AMMF 11 and / or AMCF 12, may be present on the compute node(s) or within the wireless communication network as AF 42 or as another new wireless communication network function.

[0044] Furthermore, in addition to the dynamic adaptation of the application migration process based on network information, the network can be adapted based on the information provided by the AMMF 11 and the measures executed by the AMCF 12. This can advantageously be done end-to-end, enabling, for example, the provision of a suitable data rate from device 20 to a cloud destination node or cloud component 30, or at least by configuring the radio access network either via the NEF 41, the PCF 43, etc., or via an intelligent radio controller in an Open RAN system, or via another interface or abstraction layer capable of configuring parameters of the radio access network, the core network, or the transport network.

[0045] In Fig.Figure 2 further illustrates the exchange of information between the components by means of arrows, according to embodiments of the invention. Information about the function to be outsourced or the application to be migrated can be received by the AMMF 11 (or the application itself) and distributed according to embodiments of the invention. Such information can include, for example, the type of application, such as a categorization of safety criticality, for example, ASIL levels according to the communication requirements; the state of the application, such as active or inactive, or required to be active at a certain time; or requirements for the availability of the functions, such as a time requirement, e.g., a time budget or a target completion time for the migration of the application.

[0046] Furthermore, information from the computer side, provided before or during the migration process by AMMF 11 and AMCF 12, can be a type, state, and / or requirement of the application migration process. This can include a memory quantity related to the application being migrated, such as a memory delta, and / or an amount of memory changed relative to the state of the application being migrated. The rate at which memory is changed for stateful applications being migrated can depend on the state of the end device, for example, a vehicle performing a specific maneuver or a robot performing a specific (collaborative) action.Furthermore, the information may include the temporal locality of memory pages and / or information about the configuration of the application migration process, such as parameter settings for delta encoding, information deduplication, or compression.

[0047] According to embodiments of the invention, information from the wireless communication network received by the NEF 41 or AF 42 or an Open RAN service can include, for example, any past and present measurements as well as future predictions about the performance of the wireless link and / or the payload, including a signal-to-noise ratio (SNR), a signal-to-interference-to-noise ratio (SINR), radio resource utilization, spectral efficiency, throughput, latency, or packet error rate. Furthermore, it can include any performance guarantee that the communication system can provide for the data stream in connection with the function offloading process, including, for example, a guaranteed bit rate (GBR), a guaranteed latency, or a reserved radio resource.

[0048] Furthermore, according to embodiments of the invention, the migration management function 10 can initiate various adaptive measures before or during the application migration to optimize the successful completion of the function migration process. From the edge cloud computing component 30, such adjustments can involve a selection of parameters for controlling the application migration process. This can include, for example, transferring the base image when network capacity is high and / or high GBR (Global Base Rate) is available. In addition, this can also include foregoing data deduplication, compression, and / or delta coding when network performance is high, thereby ensuring a high probability that the timing and availability requirements of the function migration process will be met.

[0049] Furthermore, according to embodiments of the invention, adjustments on the wireless communication network side include, for example, prioritizing application migration over other services by selecting higher-priority QoS profiles. Alternatively, the data rate (GBR, higher GBR QoS profile, scheduler setting) can be increased as the target migration completion time approaches. It is also possible to adjust the data rate (GBR, higher GBR QoS profile, scheduler setting) when memory pages that are frequently modified need to be transferred (temporary locality, see prior art), or to establish a dedicated network segment with fixed performance guarantees for offloading highly critical functions.

[0050] According to one embodiment of the invention, an application migration time model can be used. This model can include an analytical description of the time required to migrate a VM / image / state machine of an application from device 20 to a cloud 30, taking environmental influences into account. Such influences can include the number of other mobile users using the same original and / or target edge cloud 30 and their respective application requirements, the dynamics of the radio channel, and the dynamics of the application process itself. This dynamic can be predicted, for example, using machine learning with a suitable output that could help inform the wireless communication network appropriately so that it can adapt accordingly.Possible information that the model can provide includes a probability distribution function (PDF) of the expected time at which the migration process will be completed. This PDF can contain information about the probability that the migration process might exceed the time constraints and may be time-dependent, which must be taken into account. The model providing the PDF could be, for example, a neural network, a system of stochastic differential equations, stochastic processes, or a Monte Carlo simulation. If, for instance, this probability of unavailability is too high, the data transfer of the migration process can be prioritized by, for example, allocating more wireless resources or a higher GBR (Globally Compatible Rate).Alternatively, instead of this probability, the system can calculate a target data rate that the mobile network must provide to meet the availability requirement. Two options for the PDF time variance detection system are available: either it can be measurement-based, meaning it measures the new (increased) data rate and recalculates the aforementioned probabilities based on these measurements; or, secondly, the wireless communication network can provide this information to function 10 and use it directly.

[0051] In another embodiment, the migration management function 10 or the AMMF 11 and / or the AMCF 12 can be extended to the device 20 to monitor and configure the function migration process. Thus, the application migration can alternatively be performed on the device 20, and appropriate interfaces are provided between it and the device 20. This means that a UE control plane can establish a logical connection to the other network functions in the 3GPP core network 40, such as the NEF 41, the PCF 43, and / or the AF 42.

[0052] According to further embodiments of the invention, the application migration can be carried out taking into account the environmental factors of the wireless communication network. The network can be involved in the migration process, particularly with regard to triggering or terminating the process based on (predicted) performance information from the communication system. It may be appropriate to trigger a functional migration process (earlier than planned). This can be advantageous if a deterioration in communication performance is expected that would jeopardize the timing and availability constraints if the process were triggered later. Furthermore, the wireless communication network can be involved based on specific requirements, the migration process, and / or network performance. The network may indicate that it cannot meet the timing and availability requirements.In this case, the offloading process can be stopped. As a result, the function remains active at the source node (i.e., the end device, such as a vehicle), and / or the application transitions to a fail-safe, failover state. Other triggers for network-induced actions can include, for example, the network determining the current and future location of the end device via location services (part of the wireless communication network), the application and / or device (vehicle) status, or initiating joining / leaving a private communication group, such as a subnetwork or a personal IoT network.

[0053] The above discussion of embodiments describes the present invention in the context of examples. Naturally, individual features of the embodiments can be freely combined with one another, provided this is technically feasible without departing from the scope of the present invention.

Claims

[1] Method (100) for initiating a migration of an application over a wireless connection, wherein a migration management function (10) performs the following steps: - Providing (101) an interface from a device within a cellular, preferably wireless, communication network to a cloud component and / or to a core network component of the wireless communication network, wherein the interface enables the initiation of the migration of the application over the wireless connection; - Receiving (102) information regarding the application in relation to a type and / or condition and / or requirement for the migration of the application; - Receiving (103) network information regarding the wireless connection between the device and the cloud component with respect to at least one wireless connection performance indicator; - Distributing (104) the received application and / or network information to each of the components via the provided interface(s) to enable the migration of the application; - Initiating (105) the migration of the application over the wireless connection based on the distributed information. [2] Method (100) according to claim 1, characterized by , that the procedure (100) includes the following further step: - Initiating, on the cloud component and / or the core network component and / or a component of the radio access network of the wireless communication network, an adaptation of a configuration for the migration of the application based on the distributed information, wherein the initiation (105) is further based on the adapted configuration on the cloud component and / or the core network component and / or the component of the radio access network. [3] Method (100) according to claim 2, characterized by, that the procedure (100) includes the following further step: - Initiate, on the core network component and / or the cloud component, an adjustment of the configuration for the migration of the application based on a time model for the application migration, wherein the model provides a dynamic probability estimate for the required migration time, based on an assessment of an expected time required for the migration of the application in relation to different environmental influences. [4] Method (100) according to any one of the preceding claims, characterized by , that the procedure (100) includes the following further step: - Monitoring the migration of the application before and during the migration process based on the distributed information. [5] Method (100) according to any one of the preceding claims, characterized by, that after initiation (105) the procedure (100) includes at least one of the following further steps: - Initiating a migration of an image of the virtual machines and / or a containerized application and / or a microservice from one cloud component to another based on the distributed information; - Initiating an adjustment of at least one control parameter for application migration with respect to memory delta encoding and / or information deduplication and / or data compression to optimize the migration of the application in terms of time and / or reliability and / or availability. [6] Method (100) according to any one of the preceding claims, characterized by , that the procedure (100) includes the following further step: - Initiating an adaptation for the migration of the application based on a prioritized quality service profile with respect to the wireless communication network. [7] Method (100) according to any one of the preceding claims, characterized by , that the procedure (100) includes the following further step: - Initiating an adaptation for the migration of the application based on the provisioning of a dedicated network slice to ensure the successful completion of the application migration. [8] Method (100) according to any one of the preceding claims, characterized by , that the procedure (100) includes at least one of the following further steps: - Initiating a determination of the current and / or future location of the device based on location services within the wireless communication network; - Initiating joining and / or leaving a private communication group within the wireless communication network. [9] Method (100) according to any one of the preceding claims, characterized by , that the migration management function (10) includes an application migration monitoring function (11) and / or an application migration control function (12), each of the functions (11, 12) being configured to monitor and control the migration of the application before and / or during the migration process. [10] Method (100) according to any one of the preceding claims, characterized by , that the migration management function (10) is assigned to the device and / or the wireless communication network and / or the cloud component. [11] Migration management function (10) for initiating a migration of an application over a wireless connection, comprising means for performing the method (100) according to any one of the preceding claims. [12] Computer program (70) comprising instructions which, when the computer program (70) is executed by a computer (10), cause the computer (10) to execute the method (100) of any one of claims 1 to 10. [13] Computer-readable storage medium (15) comprising instructions which, when executed by a computer (10), cause the computer (10) to perform the steps of the method (100) of any one of claims 1 to 10.

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