Negotiation device, negotiation method and program

Abstract

The negotiation device (2000) acquires history information 30 indicating the presentation time of the current offer from the other agent (10) and the utility of each offer from the other agent (10) that has been received in the negotiation. In the negotiation, a maximum time length of the negotiation period is determined in advance. The negotiation device (2000) generates a probability distribution of the number of future offers based on the remaining time length of the negotiation period and the presentation time of the current offer. The negotiation device (2000) calculates the expected utility of the future offer based on the probability distribution of the number of future offers and the utility indicated by the history information (30). The negotiation device (2000) determines whether to accept the current offer based on the expected utility of the future offer and the utility of the current offer.

Description

[Technical field]

[0001] The present disclosure relates generally to auto-negotiation. [Background technology]

[0002] Technologies related to automated negotiation have been developed. In automated negotiation, an agent provides an offer to the other party, and the other party accepts or rejects the offer. Non-Patent Document 1 discloses a technology that determines whether to accept an offer based on the utility of the offer, which indicates how desirable the offer is for the agent receiving the offer. [Prior art documents] [Non-patent literature]

[0003] [Non-Patent Document 1] Tim Baarslag, Koen Hindriks, “Accepting Optimally in Automated Negotiation with Incomplete Information,” Proceedings of the 12th International Conference on Autonomous Agents and Multiagent Systems (AA-MAS 2013), May 6, 2013. Summary of the Invention [Problem to be solved by the invention]

[0004] In Non-Patent Document 1, it is assumed that the maximum number of offers is determined in advance as a rule of negotiation. The present disclosure provides a new technique for appropriately determining whether or not to accept an offer in negotiation. [Means for solving the problem]

[0005] A first negotiation device provided in the present disclosure includes at least one processor and a memory storing instructions configured to execute the instructions to obtain, in a negotiation having a predetermined maximum time length, historical information indicating a presentation time of a current offer from a counterparty and a utility of each offer from the counterparty that has been received in the negotiation, generate a probability distribution of a number of future offers based on a remaining time length of the negotiation and the presentation time of the current offer, calculate an expected utility of a future offer based on the probability distribution of the number of future offers and the utility indicated by the historical information, and determine whether to accept the current offer based on the expected utility of the future offer and the utility of the current offer.

[0006] A second negotiation device provided in the present disclosure includes at least one processor and a memory storing instructions configured to execute the instructions to: obtain, for each of a plurality of counterparties in a negotiation having a predetermined maximum time length, historical information indicating a utility of each offer from the counterparty that has been received in the negotiation, calculate, for each of the plurality of counterparties, an expected utility of a future offer from the counterparty based on the utility indicated by the counterparty's historical information, determine an acceptance threshold using a maximum value of the expected utilities of the future offers, and determine whether to accept the current offer based on the utility of the current offer and the acceptance threshold.

[0007] A first negotiation method provided in the present disclosure is computer-implemented and includes obtaining historical information indicative of a presentation time of a current offer from a counterparty in a negotiation having a predetermined maximum time length and a utility of each offer from the counterparty that has been received in the negotiation, generating a probability distribution of a number of future offers based on a remaining time length of the negotiation and the presentation time of the current offer, calculating an expected utility of a future offer based on the probability distribution of the number of future offers and the utility indicated by the historical information, and determining whether to accept the current offer based on the expected utility of the future offer and the utility of the current offer.

[0008] A second computer-implemented negotiation method is provided in the present disclosure, comprising: obtaining, for each of a plurality of counterparties in a negotiation having a predetermined maximum time length, historical information indicating a utility of each offer received in the negotiation from the counterparty; calculating, for each of the plurality of counterparties, an expected utility of a future offer from the counterparty based on the utility indicated by the counterparty's historical information; determining an acceptance threshold using a maximum of the expected utilities of the future offers; and determining whether to accept the current offer based on the utility of the current offer and the acceptance threshold.

[0009] A first non-transitory computer-readable storage medium provided in the present disclosure stores a program for causing a computer to execute the first negotiation method of the present disclosure described above.

[0010] A second non-transitory computer-readable storage medium provided in the present disclosure stores a program for causing a computer to execute the second negotiation method of the present disclosure described above. Effect of the Invention

[0011] According to the present disclosure, a new technique is provided for appropriately determining whether or not to accept an offer in negotiations. [Brief description of the drawings]

[0012] [Figure 1] FIG. 1 shows an overview of the negotiation device of the first embodiment. [Diagram 2] FIG. 2 is a block diagram illustrating an example of the functional configuration of the negotiation device. [Diagram 3] FIG. 3 is a block diagram showing an example of a hardware configuration of a computer that realizes the negotiation device. [Figure 4] FIG. 4 is a flow chart showing an exemplary flow of the processing executed by the negotiation device of the first embodiment. [Diagram 5] FIG. 5 shows an exemplary structure of the history information. [Figure 6] FIG. 6 is a flow chart showing an exemplary flow of processing executed by the negotiation device of the second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] Hereinafter, exemplary embodiments of the present disclosure will be described with reference to the drawings. In each drawing, the same elements are denoted by the same reference numerals, and duplicated descriptions will be omitted as necessary. In addition, the storage unit is composed of one or more storage devices.

[0014] EMBODIMENT 1 <Summary> Fig. 1 shows an overview of the negotiation device 2000 of the first embodiment. Note that the overview shown in Fig. 1 shows an example of the operation of the negotiation device 2000 in order to make the negotiation device 2000 easier to understand, and is not intended to limit or narrow the range of operations that the negotiation device 2000 can take.

[0015] The negotiation device 2000 operates as an automated agent that negotiates with the other party's agent 10. The other party's agent 10 is an agent that provides an offer to the negotiation device 2000. The other party's agent 10 may be operated manually or automatically.

[0016] In this embodiment, it is assumed that the number of counterpart agents 10 is 1. As will be described later, the negotiation device 2000 of the second embodiment handles a plurality of counterpart agents 10.

[0017] The negotiation device 2000 negotiates with the other agent 10 under the rule that the negotiation must be completed by the negotiation deadline. In other words, the length of the negotiation period is determined in advance. Hereinafter, the negotiation period and its length are referred to as the "negotiation period" and the "maximum negotiation time", respectively.

[0018] The negotiation device 2000 receives an offer from the other agent 10 and determines whether or not to accept this offer (called the "current offer"). If the negotiation device 2000 rejects the current offer, the negotiation continues, and if the negotiation device 2000 accepts the current offer, the negotiation ends. Also, the negotiation ends when the negotiation period expires.

[0019] The decision to accept the current offer is based on the utility of the current offer, which is an index value that indicates how desirable the offer is from the perspective of the party receiving the offer. The party may be a user of the negotiation device 2000.

[0020] Conceptually, it is preferable for the negotiation device 2000 to reject the current offer and wait for a future offer when the other agent 10 is expected to make a better offer than the current offer. On the other hand, it is preferable for the negotiation device 2000 to accept the current offer when the other agent 10 is not expected to make a better offer than the current offer. Note that a future offer is any offer that the negotiation device 2000 receives in a negotiation after receiving the current offer.

[0021] Thus, the negotiation device 2000 determines whether to accept the current offer based on the utility of the current offer and the expected utility of the future offer. For example, the negotiation device 2000 may determine to accept the current offer when the utility of the current offer is greater than or equal to the expected utility of the future offer. On the other hand, the negotiation device 2000 may reject the current offer when the utility of the current offer is less than the expected utility of the future offer.

[0022] The expected utility of the future offers is calculated using history information 30. History information 30 indicates the presentation time of the current offer and the utility of each offer that negotiation device 2000 has received (i.e., the current offer and past offers). Specifically, negotiation device 2000 generates a probability distribution of the number of future offers based on the length of time remaining in the negotiation (i.e., the length of time between the current time and the deadline for the negotiation) and the presentation time of the current offer. Then, negotiation device 2000 calculates the expected utility of the future offers based on the probability distribution of the number of future offers and the utility indicated by history information 30. Hereinafter, the length of time remaining in the negotiation will be referred to as the "remaining time of the negotiation."

[0023] <Examples of effects> Unlike the negotiation assumed in Non-Patent Document 1, what is predetermined for the negotiation conducted by the negotiation device 2000 is not the maximum number of offers but the maximum length of the negotiation time. To handle this type of negotiation, the negotiation device 2000 predicts the distribution of the number of future offers based on the remaining negotiation time, and calculates the expected utility of the future offers based on the predicted distribution of the number of future offers. Then, whether to accept the current offer is determined based on the utility of the current offer and the expected utility of the future offer. In this way, the negotiation device 2000 can accurately predict whether the current offer is more preferable than the future offer in a negotiation with a fixed maximum length of time, and can thus appropriately determine whether to accept the current offer.

[0024] A more detailed description of the negotiation device 2000 of the first embodiment is provided below.

[0025] <Example of functional configuration> 2 shows an example of the functional configuration of the negotiation device 2000. The negotiation device 2000 includes an acquisition unit 2020, a prediction unit 2040, and a determination unit 2060. The acquisition unit 2020 acquires history information 30. The prediction unit 2040 generates a probability distribution of the number of future offers based on the remaining negotiation time and the presentation time of the current offer. The prediction unit 2040 calculates an expected utility of the future offer based on the probability distribution of the number of future offers and the utility indicated by the history information 30. The determination unit 2060 determines whether to accept the current offer based on the utility of the current offer and the expected utility of the future offer.

[0026] <Hardware configuration example> Negotiation apparatus 2000 may be implemented in one or more computers, each of which may be a dedicated computer created for implementing negotiation apparatus 2000 or a general-purpose computer such as a personal computer (PC), a server machine, or a mobile device.

[0027] The negotiation device 2000 can be realized by installing an application on a computer. The application is realized by a program that causes the computer to function as the negotiation device 2000. In other words, the program implements the functional components of the negotiation device 2000.

[0028] 3 is a block diagram showing an example of a hardware configuration of a computer 1000 that realizes negotiation device 2000. In FIG. 3, computer 1000 includes a bus 1020, a processor 1040, a memory 1060, a storage device 1080, an input / output interface 1100, and a network interface 1120.

[0029] The bus 1020 is a data communication path for the processor 1040, the memory 1060, the storage device 1080, the input / output interface 1100, and the network interface 1120 to transmit and receive data to and from each other. The processor 1040 is a processor such as a central processing unit (CPU), a graphics processing unit (GPU), or a field-programmable gate array (FPGA). The memory 1060 is a main storage element such as a random access memory (RAM) or a read only memory (ROM). The storage device 1080 is an auxiliary storage element such as a hard disk, a solid state drive (SSD), or a memory card. The input / output interface 1100 is an interface between the computer 1000 and a peripheral device (such as a keyboard, a mouse, or a display device). The network interface 1120 is an interface between the computer 1000 and a network. The network may be a local area network (LAN) or a wide area network (WAN).

[0030] The storage device 1080 may store the above-mentioned programs. The processor 1040 executes the programs to realize each functional component of the negotiation device 2000.

[0031] The hardware configuration of the computer 1000 is not limited to the configuration shown in FIG. For example, as previously described, negotiation device 2000 may be implemented with multiple computers, which may be connected to each other via a network.

[0032] <Processing flow> 4 is a flow chart showing an example flow of the process executed by the negotiation device 2000 of embodiment 1. Note that the flow of the process executed by the negotiation device is not limited to that shown in FIG.

[0033] The negotiation device 2000 determines whether the negotiation period has expired (S102). If the negotiation period has expired (S102: YES), the negotiation device 2000 ends the process shown in FIG. 4. On the other hand, if the negotiation period has not expired (S102: NO), the negotiation device 2000 determines whether a new offer has been received (S104). If the negotiation device 2000 has not received a new offer (S104: NO), the process returns to step S202. Repeated execution of steps S102 to S104 means that the negotiation device 2000 waits for a new offer as long as the negotiation period has not expired.

[0034] If the negotiation device 2000 receives a new offer (S104: YES), the acquisition unit 2020 acquires the history information 30 (S106). The new offer is treated as the current offer. The prediction unit 2040 generates a probability distribution of the number of future offers based on the remaining negotiation time and the presentation time of the current offer (S108). The remaining negotiation time can be calculated by subtracting the current time from the deadline for negotiation. The prediction unit 2040 calculates the expected utility of the future offer based on the probability distribution of the number of future offers and the utility indicated by the history information 30 (S110).

[0035] The determination unit 2060 determines whether to accept the current offer based on the utility of the current offer and the expected utility of the future offer (S112). If the determination unit 2060 determines that the current offer is not to be accepted (S112: NO), the process returns to step S102 and the negotiation continues. On the other hand, if the determination unit 2060 determines that the current offer is to be accepted (S112: YES), the process shown in FIG. 4 ends.

[0036] <Acquisition of history information 30: S106> The acquisition unit 2020 acquires the history information 30 (S106). The history information 30 indicates the presentation time of the current offer and the utility of each offer (i.e., past offers and the current offer) that has been received by the negotiation device 2000. Note that the history information 30 may additionally indicate the presentation time of the past offer.

[0037] FIG. 5 shows an exemplary structure of the history information 30. The history information 30 has three columns: an offer identifier 32, a presentation time 34, and a utility 36. The history information has a row for each offer. The offer identifier 32 of a row indicates an identifier (e.g., a sequence number) of the offer corresponding to the row. The presentation time 34 of a row indicates the presentation time of the offer corresponding to the row, for example, the time when the negotiation device received the corresponding offer. Note that unless otherwise specified, the start time of the negotiation is set to 0, so that the presentation time of the offer corresponds to the time length from the start time of the negotiation to the time when the offer is received. The utility 36 of a row indicates the utility of the offer corresponding to the row. For example, the first row of the history information 30 shown in FIG. 5 indicates that the presentation time and utility of offer 001 are t1 and u1, respectively.

[0038] It should be noted that the utility of an offer is calculated based on one or more contents of the offer. The contents of the offer depend on the negotiation. Assume that the other agent 10 is trying to sell a product to the user of the negotiation device 2000. In this case, the offer may include the number of products, the price of the product, the delivery time of the product, etc.

[0039] In some embodiments, the utility of an offer is calculated using a utility function that takes one or more values ​​that represent the contents of the offer and outputs a real value that represents the utility of the offer. The utility function may convert each of the contents of the offer into a score and calculate a weighted sum of the scores as the utility of the offer.

[0040] Historical information 30 may be updated when negotiation device 2000 receives a current offer. Specifically, negotiation device 2000 may calculate the utility of the current offer, generate new information in historical information 30 (e.g., a new row in the table shown in FIG. 5 ) for the current offer, and add this new information to historical information 30.

[0041] There are various methods for acquiring the history information 30. In some embodiments, the history information 30 is pre-stored in a storage unit in a manner that the acquisition unit 2020 can acquire the history information 30 therefrom. In this case, the acquisition unit 2020 may access the storage unit and acquire the history information 30 from the storage unit. In other implementation forms, the acquisition unit 2020 may receive the history information 30 transmitted from another computer.

[0042] <Utility of future offers: S108, S110> As described above, the prediction unit 2040 calculates the expected utility of future offers (S110). The expected utility of future offers may depend on the number of future offers. However, since what is specified in the negotiation between the negotiation device 2000 and the other agent 10 is not the maximum number of offers but the maximum length of the negotiation, the number of future offers cannot be specified.

[0043] Therefore, the predictor 2040 may calculate the future expected utility as follows:

number

[0044] The prediction unit 2040 can calculate the expected utility E of a future offer by acquiring P(k) and E(k) and applying the acquired P(k) and E(k) to the formula (1). An example of how to calculate P(k) and E(k) will be described below.

[0045] <<Probability distribution of the number of future offers>> The predictor 2040 generates a probability distribution, i.e., P(k), of the number of future offers based on the remaining negotiation time and the presentation time of the current offer (S108). In some aspects, the probability distribution of the number of future offers can be modeled as follows:

number

[0046] The following describes how to introduce formula (2). The number of future offers received by the negotiation device 2000 may depend on the frequency with which the negotiation device 2000 receives future offers. Therefore, the probability distribution of the number of future offers can be calculated based on the probability distribution of the frequency with which the future offers are received.

[0047] The probability distribution of how often future offers will be received can be modeled as follows:

number

[0048] Using the probability distribution f(λ), the probability distribution of the number of future offers can be formulated as follows:

number

[0049] <<Utility of future offers when the number of future offers is fixed>> Negotiation device 2000 generates a conditional utility function E(k) (i.e., calculates the expected utility of future offers, conditional on the number of future offers being k). First, negotiation device 2000 predicts the distribution of the utilities of future offers, which may be predicted based on the history of the utilities of offers as indicated by history information 30.

[0050] In some aspects, the predictor 2040 uses Gaussian process regression to predict the distribution of utilities of future offers. Specifically, the predictor 2040 can calculate the difference between each pair of temporally adjacent utilities as follows:

number

[0051] The prediction unit 2040 then applies the pair of offer index and utility difference of adjacent offers (i.e., (i,Δu_i) for i=1 to c) as input to a Gaussian process regression, thereby obtaining a Gaussian distribution of utility differences of adjacent future offers. Specifically, the prediction unit 2040 can obtain a pair of mean and variance of the Gaussian distribution of utility differences of adjacent future offers.

[0052] The predictor 2040 can then generate a Gaussian distribution of the utility of the feature offers by calculating the mean and variance as follows:

number

[0053] It should be noted that since the prediction unit 2040 applies the difference in utilities between adjacent offers to the Gaussian process regression, it is possible to predict the utilities of future offers more accurately than when the utilities of offers indicated by the history information 30 are directly applied to the Gaussian process regression. However, in other embodiments, the prediction unit 2040 may directly apply the utilities of offers indicated by the history information 30 to the Gaussian process regression to obtain a Gaussian distribution of utilities of future offers. More specifically, pairs of offer indexes and utilities (i.e., (i, u_i) for i=1 to c) are fed as inputs to the Gaussian process regression to obtain a Gaussian distribution of utilities of future offers. It should be noted that u_i represents the utility of the i-th offer.

[0054] Using the distribution of utilities of future offers predicted as above, the predictor 2040 calculates the expected utility of future offers, i.e., E(k), under the condition that the number of future offers is k. The predictor 2040 can calculate E(k) as follows:

number

[0055] In order to reduce the calculation time of the above equation (7), the prediction unit 2040 may calculate equation (7) using the following equation.

number

[0056] <Acceptance decision: S108> The determination unit 2060 determines whether or not to accept the current offer based on the utility of the current offer and the expected utility of the future offer (S108). To do this, the determination unit 2060 may determine whether or not the utility of the current offer is equal to or greater than a threshold Th called an "acceptance threshold" that is defined based on the expected utility of the future offer. When the current offer is equal to or greater than the acceptance threshold, the determination unit 2060 determines to accept the current offer. On the other hand, when the current offer is smaller than the acceptance threshold, the determination unit 2060 determines to reject (in other words, not to accept) the current offer.

[0057] In some aspects, the determining unit 2060 can set the expected utility of the future offer as the acceptance threshold. In other implementations, the determining unit 2040 can set the expected utility of the future offer plus a margin as the acceptance threshold Th:Th=E+α, where E is the expected utility of the future offer and α is the margin. The margin α may be defined based on the benefit of early termination of the negotiation. The longer the remaining time of the negotiation, the larger the margin α can be defined. This is because it may be more beneficial for the user of the negotiation device 2000 to end the negotiation early than to wait for a future offer that is slightly more preferable than the current offer in terms of utility.

[0058] <Negotiation Device 2000 Output> The negotiation device 2000 may output information based on the result of the determination regarding the current offer. Hereinafter, this information will be referred to as "output information." The output information may be a response to the current offer. In this case, the negotiation device 2000 may transmit the output information to the other agent 10. The response indicates an acceptance or rejection of the current offer. Furthermore, the response may also indicate a counteroffer. It should be noted that there are various well-known methods for presenting a counteroffer based on a received offer, and one of these methods may be adopted by the negotiation device 2000.

[0059] The negotiation device 2000 may also output output information to inform the user of the negotiation device 2000 of the results of the determination regarding the current offer. In this case, the output information may include any information useful to the user, such as whether the current offer was accepted and the expected utility of future offers.

[0060] The output information may be output in a variety of ways. In some aspects, the negotiation apparatus 2000 may store the output information in a memory unit. In other embodiments, the negotiation apparatus 2000 may output the output information to a display device, causing the output information to be displayed on the display device. In other embodiments, the negotiation apparatus 2000 may transmit the output information to another computer, such as the other agent 10 or a user device (e.g., a PC or smartphone) of the user of the negotiation apparatus 2000.

[0061] EMBODIMENT 2 <Summary> The negotiation device 2000 of the second embodiment negotiates with two or more other party agents 10. Thus, the negotiation device 2000 can accept an offer from one of the multiple other party agents 10 and reject offers from the rest of them.

[0062] In order to handle multiple counterpart agents 10, the negotiation device 2000 calculates the expected utility of future offers for each counterpart agent 10, which are respectively represented as E1, E2, ..., EA (A represents the number of counterpart agents 10). In this embodiment, the negotiation device 2000 acquires history information 30 for each counterpart agent 10. The history information 30 of the counterpart agent 10 indicates the presentation time of the current offer from the counterpart agent 10 and the utility of each offer from the counterpart agent 10 received by the negotiation device 2000.

[0063] The negotiation device 2000 of the second embodiment, like the negotiation device 2000 of the first embodiment, determines whether to accept the current offer by comparing the utility of the current offer with an acceptance threshold. However, the method by which the negotiation device 2000 of the second embodiment determines the acceptance threshold is different from the method used by the negotiation device 2000 of the first embodiment. Specifically, the negotiation device 2000 determines the acceptance threshold based on a set of expected utilities of future offers calculated for each of the other agents 10, i.e., {E1, E2, ..., EA}. Hereinafter, this set will be referred to as an "expected utility set" and denoted as S (i.e., S={E1, E2, ..., EA}). For example, the maximum value in the expected utility set S may be set as the acceptance threshold.

[0064] <Examples of effects> The negotiation device 2000 of the second embodiment can appropriately determine whether to accept a current offer in a negotiation in which multiple counterparties are present and the maximum time length of the negotiation is predetermined, rather than the maximum number of future offers.

[0065] A more detailed description of the negotiation device 2000 of the second embodiment is given below.

[0066] <Example of functional configuration> The functional configuration of the negotiation device 2000 of embodiment 2 may be as shown in Fig. 2, similar to the negotiation device 2000 of embodiment 1. The acquisition unit 2020 of embodiment 2 acquires history information 30 for each other agent 10. For each other agent 10, the prediction unit 2040 calculates the expected utility of a future offer from the other agent 10. The determination unit 2060 determines an acceptance threshold based on the expected utility of a future offer from each other agent 10, and determines whether to accept the current offer based on the utility of the current offer and the acceptance threshold.

[0067] <Hardware configuration example> The negotiation device 2000 of the second embodiment may be realized by one or more computers similar to those that realize the negotiation device 2000 of the first embodiment. Therefore, the hardware configuration may also be as shown in Fig. 3. However, the storage device 1080 of the second embodiment may include a program for causing the computer 1000 to function as the negotiation device 2000 of the second embodiment.

[0068] <Processing flow> 6 is a flow chart showing an example flow of the process executed by the negotiation device 2000 of embodiment 2. Note that the flow of the process executed by the negotiation device is not limited to that shown in FIG.

[0069] The negotiation device 2000 initializes an expected utility set (S202). The expected utility set may be initialized to indicate 0 for each other agent. The negotiation device 2000 of embodiment 2 then waits for new offers (S204 and S206) as long as the negotiation period has not expired, similar to the negotiation device 2000 of embodiment 1.

[0070] When it is determined that the negotiation device 2000 has received a new offer (S206: YES), the prediction unit 2040 calculates the expected utility of a future offer from the other agent 10 that has transmitted the new offer (i.e., the current offer) (S208). Hereinafter, the other agent 10 that has transmitted the current offer is referred to as the "current other agent." The prediction unit 2040 updates the expected utility set with the expected utility of a future offer from the current other agent calculated in step S208 (S210). The determination unit 2060 determines an acceptance threshold using the expected utility set updated in step S210 (S212).

[0071] The determination unit 2060 determines whether the utility of the current offer is equal to or greater than the acceptance threshold (S214). If the utility of the current offer is equal to or greater than the acceptance threshold (S214: YES), the determination unit 2060 determines to accept the current offer (S218). Thus, the process shown in FIG. 6 ends. On the other hand, if the utility of the current offer is not equal to or greater than the acceptance threshold (S214: NO), the determination unit 2060 determines to reject the current offer (S216). Thus, the process shown in FIG. 6 returns to S204, and the negotiation continues.

[0072] <Calculating expected utility of future offers: S208> In response to the negotiation device 2000 receiving a new offer, the prediction unit 2040 calculates the expected utility of a future offer from the current other agent (S208). To do this, the acquisition unit 2020 acquires the history information 30 of the current other agent. The prediction unit 2040 then generates a probability distribution of the number of future offers from the current other agent, which corresponds to P(k) in equation (1), based on the remaining negotiation time and the presentation time of the current offer. A specific method for generating the probability distribution of the number of future offers from the other agent 10 has already been described in embodiment 1.

[0073] The prediction unit 2040 also calculates the expected utility of a future offer from the current other agent when the number of future offers (corresponding to E(k) in equation (1)) is given, based on the utility indicated by the current other agent's history information 30. A specific method for calculating the expected utility of a future offer from a other agent when the number of future offers is given has already been described in embodiment 1.

[0074] Then, the prediction unit 2040 calculates the expected utility of a future offer from the current other agent without the condition of the number of future offers (corresponding to E in formula (1)) based on the expected utility of a future offer from the current other agent when the number of future offers is given and the probability distribution of the number of future offers from the current other agent. In other words, the prediction unit 2040 applies P(k) and E(k) of the current other agent to formula (1) to calculate the expected utility E of the current other agent.

[0075] <Update of expected utility set: S210> The prediction unit 2040 updates the expected utility set with the expected utility of a future offer from the current other agent. Assume that an element S[i] of the expected utility set S represents the expected utility of a future offer from a other agent 10 having an identifier i, and the current other agent has an identifier j. In this case, the prediction unit 2040 updates S[j] with the expected utility of a future offer from the current other agent calculated in step S208.

[0076] <Determining the acceptance threshold: S212> The determination unit 2060 uses the expected utility set to determine the acceptance threshold. Essentially, if the expected utility set contains a value that is greater than the utility of the current offer, it is preferable for the negotiation device 2000 not to accept the current offer because the negotiation device 2000 is expected to receive a more favorable offer than the current one.

[0077] Thus, in some aspects, the negotiation device 2000 may set the acceptance threshold to the maximum value in the expected utility set S. In this case, the negotiation device 2000 will decide to accept the current offer only if the utility of the current offer is greater than or equal to the expected utilities of all future offers from the current counterpart agent 10.

[0078] In another embodiment, similar to embodiment 1, negotiation device 2000 of embodiment 2 can include a margin in the acceptance threshold. Specifically, determination unit 2040 can set the acceptance threshold Th:Th=EL+α to the maximum value in the expected utility set plus the margin, where EL is the maximum value in the expected utility set and α is the margin.

[0079] <End of negotiations> The negotiation device 2000 terminates negotiations with multiple other agents 10 upon accepting the current offer. For example, the negotiation device 2000 notifies each other agent 10 of the termination of the negotiation. With respect to the current other agent, the negotiation device 2000 can transmit a response indicating acceptance of the current offer. This response can also signify the termination of the negotiation.

[0080] Although the present disclosure has been described with reference to the embodiment, the present disclosure is not limited to the above-mentioned embodiment. Various modifications that can be understood by a person skilled in the art can be made to the configuration and details of the present disclosure within the scope of the present disclosure.

[0081] The program in the present disclosure includes a set of instructions (or software code) that, when loaded into a computer, causes the computer to perform one or more functions described in the embodiments. The program may be stored in a non-transitory computer-readable medium or a tangible storage medium. By way of example and not limitation, the computer-readable medium or tangible storage medium includes random-access memory (RAM), read-only memory (ROM), flash memory, solid-state drive (SSD) or other memory technology, CD-ROM, digital versatile disc (DVD), Blu-ray® disk or other optical disk storage, magnetic cassette, magnetic tape, magnetic disk storage or other magnetic storage device. The program may be transmitted on a transitory computer-readable medium or communication medium. By way of example and not limitation, the transitory computer-readable medium or communication medium includes electrical, optical, acoustic, or other forms of propagated signals.

[0082] This application claims priority based on Japanese Patent Application No. 2021-214132, filed on December 28, 2021, the disclosure of which is incorporated herein in its entirety. [Explanation of symbols]

[0083] 10 Opponent Agent 30 Historical Information 32 Offer Identifier 34 Presentation Time 36 Benefits 1000 Computers 1020 Bus 1040 Processor 1060 Memory 1080 Storage Device 1100 Input / Output Interface 1120 Network Interface 2000 Negotiation Device 2020 Acquisition Department 2040 Prediction Department 2060 Judgment section

Claims

1. At least one processor; a memory storing instructions; The at least one processor executes the instructions to: In a negotiation in which a maximum time length of a period is predetermined, historical information is obtained that indicates a time when a current offer is presented from a counterparty and a utility of each offer that has been received from the counterparty in the negotiation; generating a probability distribution for a number of future offers based on a length of time remaining in the negotiation and the presentation time of the current offer; calculating an expected utility of future offers based on the probability distribution of the number of future offers and the utility indicated by the historical information; A negotiation device configured to determine whether to accept the current offer based on expected utilities of the future offers and the utility of the current offer.

2. 2. The negotiation device of claim 1, wherein the generating of the probability distribution of the number of future offers comprises applying the length of time of the remaining period of the negotiation and the presentation time of the current offer to parameters of a predefined model of the probability distribution of the number of future offers.

3. The calculation of expected utility of the future offers comprises: generating a conditional expected utility function that takes the number of future offers as an input and outputs an expected utility of the future offers conditional on the number of future offers being represented by the input; and calculating an expected utility of the future offers based on the conditional expected utility function and the probability distribution of the number of future offers.

4. The generation of the conditional expected utility function comprises: calculating a utility difference for each pair of utilities that are adjacent in time as indicated by the historical information; applying a Gaussian process regression to the calculated differences in utility to obtain a Gaussian distribution of differences in utility for the future offers; and calculating an expected utility of each of the future offers based on the Gaussian distribution of utility differences in the future offers.

5. The negotiation is conducted between a plurality of the parties; an expected utility of the future offers is calculated for each of the parties; The determination of whether to accept the current offer comprises: determining an acceptance threshold using a maximum of the expected utility of future offers; and determining to accept the current offer if the utility of the current offer is greater than or equal to the acceptance threshold.

6. At least one processor; a memory storing instructions; The at least one processor executes the instructions to: obtaining, for each of a plurality of counterparties in a negotiation, historical information indicating a utility of each offer from the counterparty that has been received in the negotiation, in a negotiation having a predetermined maximum time length; calculating, for each of the plurality of counterparties, an expected utility of a future offer from the counterparty based on the utility indicated by the historical information of the counterparty; determining an acceptance threshold using the maximum expected utility of the future offers; A negotiation device configured to determine whether to accept the current offer based on the utility of the current offer and the acceptance threshold.

7. obtaining historical information indicating a time of a current offer from a counterparty in a negotiation having a predetermined maximum time length and a utility of each offer from the counterparty that has been received in the negotiation; generating a probability distribution for a number of future offers based on a length of time remaining in the negotiation and the presentation time of the current offer; calculating an expected utility of future offers based on the probability distribution of the number of future offers and the utility indicated by the historical information; determining whether to accept the current offer based on expected utilities of the future offers and the utility of the current offer.

8. obtaining, for each of a plurality of counterparties in a negotiation, the maximum time length of the negotiation period being predetermined, historical information indicating a utility of each offer from the counterparty that has been received in the negotiation; calculating, for each of the plurality of counterparties, an expected utility of future offers from the counterparty based on the utility indicated by the historical information of the counterparty; determining an acceptance threshold using a maximum of the expected utility of future offers; determining whether to accept the current offer based on the utility of the current offer and the acceptance threshold.

9. obtaining historical information indicating a time of a current offer from a counterparty in a negotiation having a predetermined maximum time length and a utility of each offer from the counterparty that has been received in the negotiation; generating a probability distribution for a number of future offers based on a length of time remaining in the negotiation and the presentation time of the current offer; calculating an expected utility of future offers based on the probability distribution of the number of future offers and the utility indicated by the historical information; and determining whether to accept the current offer based on expected utilities of the future offers and the utility of the current offer.

10. obtaining, for each of a plurality of counterparties in a negotiation, the maximum time length of the negotiation period being predetermined, historical information indicating a utility of each offer from the counterparty that has been received in the negotiation; calculating, for each of the plurality of counterparties, an expected utility of future offers from the counterparty based on the utility indicated by the historical information of the counterparty; determining an acceptance threshold using a maximum of the expected utility of future offers; and determining whether to accept the current offer based on the utility of the current offer and the acceptance threshold.

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