Abstract: One or more implementations of the present specification provide an invoice access method and apparatus based on a blockchain, and an electronic device. The method includes: generating first ciphertext data by encrypting plaintext data of the target invoice based on a first key corresponding to an invoice issuer; generating second ciphertext data by encrypting the plaintext data of the target invoice based on a second key corresponding to an invoice receiver; adding the first ciphertext data and an user identifier of the invoice issuer to the blockchain as related to one another; and adding the second ciphertext data and an user identifier of the invoice receiver to the blockchain as related to one another.

Abstract: One or more implementations of the present specification provide an invoice invalidation method and apparatus based on a blockchain, and an electronic device. The method includes: receiving an invalidation request that is initiated by an invoice invalidation party for a target invoice recorded in the blockchain; in response to the invalidation request, determining whether the invoice invalidation party has authority to invalidate the target invoice; and in response to that the invoice invalidation party has the authority to invalidate the target invoice, invoking an invoice invalidation logic provided in a smart contract deployed in a blockchain network of the blockchain to invalidate the target invoice.

Abstract: One or more implementations of the present specification provide an invoice access method and apparatus based on a blockchain, and an electronic device. The method includes: receiving an access request initiated by an access user for a target invoice by using a client, the target invoice being encrypted and stored in the blockchain; determining, in response to the access request, whether the access user has an authority to access the target invoice; and in response to that the access user has the authority to access the target invoice, invoking decryption logic provided in a predetermined smart contract to decrypt ciphertext data of the target invoice stored in the blockchain, and returning decrypted plaintext data of the target invoice to the client.

Abstract: A method (1) is described for training a machine learning model (2) to receive as input a time-resolved three-dimensional model (4) of a heart or a portion of a heart, and to output (3) a predicted time-to-event or a measure of risk for an adverse cardiac event. The method includes receiving a training set (5). The training set (5) includes a number of time-resolved three-dimensional models (41, . . . , 4N) of a heart or a portion of a heart. The training set (5) also includes, for each time-resolved three-dimensional model (41, . . . , 4N), corresponding outcome data (71, . . . , 7N) associated with the time-resolved three-dimensional model (41, . . . , 4N). The method (1) of training a machine learning model (2) also includes, using the training set (5) as input, training the machine learning model (2) to recognise latent representations (12) of cardiac motion which are predictive of an adverse cardiac event.

Abstract: Implementations of the present specification provide methods, apparatuses, and electronic devices for resource allocation based on blockchain. The blockchain stores a mapping relationship between a digital digest of an invoice and a resource allocation state corresponding to the invoice. The method includes: receiving a target transaction submitted by a client to participate in resource allocation based on a target invoice; in response to the target transaction, calculating a digital digest of the target invoice, and querying a resource allocation state stored in the blockchain and corresponding to the digital digest; and if the detected resource allocation state is an unallocated state, invoking resource allocation logic declared in a smart contract published in the blockchain, to allocate resources to the client from a predetermined resource pool based on a predetermined allocation rule, and returning a resource allocation result to the client.

Abstract: One or more implementations of the present specification provide an invoice access method and apparatus based on a blockchain, and an electronic device. The method includes: receiving an access request initiated by an access user for a target invoice by using a client, the target invoice being encrypted and stored in the blockchain; determining, in response to the access request, whether the access user has an authority to access the target invoice; and in response to that the access user has the authority to access the target invoice, invoking decryption logic provided in a predetermined smart contract to decrypt ciphertext data of the target invoice stored in the blockchain, and returning decrypted plaintext data of the target invoice to the client.

Abstract: Implementations of the present specification provide methods, apparatuses, and electronic devices for resource allocation based on blockchain. The blockchain stores a mapping relationship between a digital digest of an invoice and a resource allocation state corresponding to the invoice. The method includes: receiving a target transaction submitted by a client to participate in resource allocation based on a target invoice; in response to the target transaction, calculating a digital digest of the target invoice, and querying a resource allocation state stored in the blockchain and corresponding to the digital digest; and if the detected resource allocation state is an unallocated state, invoking resource allocation logic declared in a smart contract published in the blockchain, to allocate resources to the client from a predetermined resource pool based on a predetermined allocation rule, and returning a resource allocation result to the client.

Abstract: One or more implementations of the present specification provide an invoice invalidation method and apparatus based on a blockchain, and an electronic device. The method includes: receiving an invalidation request that is initiated by an invoice invalidation party for a target invoice recorded in the blockchain; in response to the invalidation request, determining whether the invoice invalidation party has authority to invalidate the target invoice; and in response to that the invoice invalidation party has the authority to invalidate the target invoice, invoking an invoice invalidation logic provided in a smart contract deployed in a blockchain network of the blockchain to invalidate the target invoice.

Abstract: One or more implementations of the present specification provide an invoice access method and apparatus based on a blockchain, and an electronic device. The method includes: receiving an access request initiated by an access user for a target invoice by using a client, the target invoice being encrypted and stored in the blockchain; determining, in response to the access request, whether the access user has an authority to access the target invoice; and in response to that the access user has the authority to access the target invoice, invoking decryption logic provided in a predetermined smart contract to decrypt ciphertext data of the target invoice stored in the blockchain, and returning decrypted plaintext data of the target invoice to the client.