The present application claims the priority and benefit of Chinese Patent Application No. 2020104797441, filed on May 29, 2020. The disclosure of the above application is incorporated herein by reference in its entirety.
The present disclosure relates to the field of computer technologies, and particularly to a natural language processing technology in artificial intelligence (AI), and in particular, to a method for training a language model, an electronic device and a readable storage medium.
In the field of natural language processing (NLP) of Chinese, a self-supervised pre-training process of a language model is performed using a large amount of unsupervised text, and then, parameters of the language model are finely timed using supervised task data, which is an advanced language-model training technology in the field of NLP.
In the existing art, in order to prevent the training effect of the language model from being influenced by the performance of a word segmenter, the self-supervised pre-training process of the language model is performed based on character granularity, such that it is difficult for the language model to learn information with greater semantic granularity (for example, words), an information leakage risk may exist, and the process of learning the semantics of the words by the language model may be damaged, thereby influencing the prediction performance of the language model.
Various aspects of the present application provide a method and apparatus for training a language model, an electronic device and a readable storage medium, so as to enhance the capacity of the language model to learn word meaning information, and avoid an information leakage risk caused by a learning process based on character granularity.
According to a first aspect, there is provided a method for training a language model, including: pre-training the language model using preset text language materials in a corpus; replacing at least one word in a sample text language material with a word mask respectively to obtain a sample text language material including at least one word mask; inputting the sample text language material including the at least one word mask into the language model, and outputting by the language model a context vector of each of the at least one word mask; determining a word vector corresponding to each word mask based on the context vector of the word mask and a word vector parameter matrix; and training the language model based on the word vector corresponding to each word mask until a preset training completion condition is met.
According to a second aspect, there is provided an apparatus for training a language model, including: a pre-training unit configured to pre-train the language model using preset text language materials in a corpus; a replacing unit configured to replace at least one word included in at least one sample text language material with a word mask respectively to obtain a sample text language material including at least one word mask; the language model configured to receive the sample text language material including the word mask, and output a context vector of each of the at least one word mask; a determining unit configured to determine a word vector corresponding to each word mask based on the context vector of the word mask and a word vector parameter matrix; and a training unit configured to train the language model based on the word vector corresponding to each word mask until a preset training completion condition is met.
According to a third aspect, there is provided an electronic device, including: at least one processor; and a memory connected with the at least one processor communicatively; wherein the memory stores instructions executable by the at least one processor to cause the at least one processor to perform the method of the aspect as described above and any possible implementation.
According to a fourth aspect, there is provided a non-transitory computer-readable storage medium with computer instructions stored thereon, wherein the computer instructions are used for causing a computer to perform the method of the aspect as described above and any possible implementation.
From the above-mentioned technical solution of embodiments of the present application, the language model is pre-trained using the preset text language materials in the corpus, the at least one word in the sample text language material is then replaced with the word mask respectively to obtain the sample text language material including the at least one word mask, the sample text language material including the at least one word mask is input into the language model, the context vector of each of the at least one word mask is output via the language model, the word vector corresponding to each word mask is determined based on the context vector of the word mask and the word vector parameter matrix, and the language model is trained based on the word vector corresponding to each word mask until the preset training completion condition is met, such that the trained language model may be obtained. Semantic information representation with greater granularity is introduced, the word vectors contain richer semantic information representation compared with character vectors, and the word vectors are modeled based on contexts, thus enhancing the process of modeling the word meaning information by the language model and the capacity of the language model to learn the word meaning information.
In addition, with the technical solution of the present application, since the word in the sample text language material is replaced with the word mask to train the language model, the information leakage risk possibly caused by character-based full word coverage may be avoided effectively.
In addition, with the technical solution of the present application, the prediction performance of the language model may be improved effectively.
It should be understood that the statements in this section are not intended to identify key or critical features of the embodiments of the present disclosure, nor limit the scope of the present disclosure. Other features of the present disclosure will become apparent from the following description.
In order to more clearly explain the technical solutions of the embodiments of the present application, the drawings to he used in the descriptions of the embodiments or the existing art are briefly introduced as follows. Apparently, the following drawings illustrate some embodiments of the present application, and a person skilled in the art can obtain other drawings from these drawings without any creative effort. The drawings are only used for better understanding the present solution and do not constitute a limitation of the present application. In the drawings:
The following part will illustrate exemplary embodiments of the present application with reference to the figures, including various details of the embodiments of the present application for a better understanding. The embodiments should he regarded only as exemplary ones. Therefore, those skilled in the art should appreciate that various changes or modifications can be made with respect the embodiments described herein without departing from the scope and spirit of the present application. Similarly, for clarity and conciseness, the descriptions of the known functions and structures are omitted in the descriptions below.
Apparently, the embodiments to be described are merely a part rather than all of the embodiments of the present application. All other embodiments obtained by a person of ordinary skill in the art based on the embodiments of the present application without creative efforts shall fall within the protection scope of the present application.
It should be noted that a terminal in the embodiments of the present application may include, but is not limited to, a mobile phone, a personal digital assistant (PDA), a wireless handheld device, a tablet computer, a personal computer (PC), an MP3 player, an MP4 player, a wearable device (for example, smart glasses, smart watches, smart bracelets, or the like), a smart home device, and other smart devices.
In addition, the term “and/or” only describes an association relationship between associated objects, and indicates that three relationships may exist. For example, A and/or B may indicate three cases: only A exists; both A and B exist; and only B exists. In addition, in this specification, the symbol “/” generally indicates that associated objects before and after have a relationship of “or”.
In the existing art, the self-supervised pre-training process of a language model is performed based on character granularity, such that it is difficult for the language model to learn information with greater semantic granularity (for example, words), an information leakage risk may exist, and the process of learning the semantics of words by the language model may be damaged, thereby influencing the prediction performance of the language model.
For example, in the pre-training process of an enhanced representation from knowledge Integration (ERNIE) model in an existing language model, the ERNIE model learns the expression of entities by means of character-based whole word mask. However, the character-based whole word mask method still does not explicitly introduce information with greater semantic granularity, for example, word vectors; in addition, an information leakage risk may exist; for example, for a text “(ha)(er)(bin)(shi)(hei)(long)(jiang)(de)(sheng)(hui) (which means in English: HarBin is the provincial capital of Heilongjiang province”, the characters “(ha)”, “(er)” and “(bin)” are replaced by three masks respectively to obtain “[mask][mask][mask](shi)(hei)(long) (jiang)(de)(sheng)(hui)”, and the ERNIE model is expected to learn that three [mask]s correspond to the three characters “(ha)”, “(er)” and “(bin)” respectively, which is equivalent to informing the ERNIE model in advance that information to be predicted consists of three characters, and such information may destroy the process of learning the semantics of the words by the model.
In order to solve the above-mentioned problems, the present application provides a method and apparatus for training a language model, an electronic device and a readable storage medium, so as to enhance the capacity of the language model to learn word meaning information, and avoid an information leakage risk caused by a learning process based on character granularity.
101: pre-training the language model using preset text language materials in a corpus.
The pre-training the language model using the preset text language materials in the corpus enables the language model to learn words, entities and entity relationships in the text language materials.
102: replacing at least one word in a sample text language material with a word mask respectively to obtain a sample text language material including at least one word mask.
The sample text language, material may be one of the preset text language materials in the corpus, or another text language material different from the preset text language materials in the corpus.
Optionally, in a possible implementation of this embodiment, when the at least one word in the sample text language material is replaced with the word mask respectively, a context of the word mask is still represented based on characters.
103: inputting the sample text language material including the at least one word mask into the language model, and outputting by the language model a context vector of each of the at least one word mask.
104: determining a word vector corresponding to each word mask based on the context vector of the word mask and a word vector parameter matrix.
105: training the language model based on the word vector corresponding to each word mask until a preset training completion condition is met.
The above-mentioned 102-105 may be an iterative execution process, the language model is trained by executing 102-105 iteratively, and when the preset training completion condition is met, the training process of the language model is completed.
Optionally, in a possible implementation of this embodiment, the preset training completion condition may be set according to an actual requirement, and for example, may include: the perplexity of the word vector output by the language model corresponding to the sample text language material reaches a first preset threshold; and/or the number of training times (i.e., the number of iterative execution times of 101-104) of the language model reaches a second preset threshold.
It should be noted that part or all of execution subjects of 101-105 may be configured as an application located at a local terminal, or a functional unit, such as a plug-in or software development kit (SDK) provided in the application located at the local terminal, or the like, or a processing engine located at a network-side server, which is not particularly limited in this embodiment.
It may be understood that the application may be configured as a native application (nativeApp) installed at the terminal, or a web application (webApp) of a browser at the terminal, which is not limited in this embodiment.
For example, in an example, the language model is pre-trained using the preset text language materials in the corpus, ““(ha)(er)(bin)” “(hei)(long)(jiang)” (which means in English: “Harbin” is the provincial capital of “Heilongjiang”)”, and ““(ha)(er) (bin)”(bing)(xue)(cheng)(shi)(which means in English: “Harbin” is an icy and snowy city)” are learned, the “(ha)(er)(bin)” in the sample text language material “(ha)(er)(bin)(shi)(hei)(long)(jiang)(de)(sheng)(hui)” is replaced by a word mask input into the language model, a word vector is output via the language model, and the language model is trained based on whether the word vector output by the language model is correct or not, such that after the training process is completed, the language model may correctly output the word vector of the “(ha) (er)(bin)” when “[mask](shi)(hei)(long)(jiang)(de)(sheng)(hui)” is input into the language model.
In this embodiment, the language model is pre-trained using the preset text language materials in the corpus, at least one word in the sample text language material is then replaced with a word mask respectively to obtain the sample text language material including the at least one word mask, the sample text language material including the at least one word mask is input into the language model, the context vector of each of the at least one word mask is output via the language model, the word vector corresponding to each word mask is determined based on the context vector of the word mask and the word vector parameter matrix, and the language model is trained based on the word vector corresponding to each word mask until the preset training completion condition is met, such that the trained language model may be obtained. Since semantic information representation with greater granularity is introduced, the word vectors contain richer semantic information representation compared with character vectors, and when the word vectors are modeled based on contexts, the process of modeling the word meaning information by the language model is enhanced, and the capacity of the language model to learn the word meaning information is enhanced.
In addition, with the technical solution of the present application, since the word in the sample text language material is replaced with the word mask to train the language model, the information leakage risk possibly caused by character-based full word coverage may be avoided effectively.
In addition, with the technical solution of the present application, the prediction performance of the language model may be improved effectively.
Optionally, in a possible implementation of this embodiment, in 102, word segmentation may be performed on the sample text language material, and each of the at least one word in the sample text language material may be replaced with one word mask based on the word segmentation result. The context of the word mask is still represented based on characters in the sample text language material except for the word replaced with the mask.
In this implementation, word segmentation is perforated on the sample text language material, the words in the sample text language material may be accurately determined according to the word segmentation result, and each of one or more of the words may be replaced respectively by one word mask, such that one or more word masks may be correctly set for training the language model, the word vectors are modeled based on contexts by the language model, the process of modeling word meaning information by the language model is enhanced, and the capacity of the language model to learn the word meaning information is enhanced.
Optionally, in a possible implementation of this embodiment, in 104, the context vector of each word mask may be multiplied by the word vector parameter matrix to obtain probability values of the word mask corresponding to the plural word vectors; then, the probability values of the word mask corresponding to the plural word vectors are normalized, for example, by a normalization index function (softmax), so as to obtain a plurality of normalized probability values of the word mask corresponding to the plurality of word vectors, and then, the word vector corresponding to the word mask is determined based on the plurality of normalized probability values of the word mask corresponding to the plurality of word vectors; specifically, the word vector with the highest normalized probability value is determined as the word vector corresponding to the word vector. When the probability values of each word mask corresponding to the plural word vectors are normalized by softmax, the word vector parameter matrix may also be referred to as a softmax parameter matrix or softmax word vector parameter matrix.
In an implementation, possible words may be included in a vocabulary, the word vector parameter matrix includes specific representation of a plurality of word vectors, the word vectors in the word vector parameter matrix are specific representation of word vectors of the words in the vocabulary, matrix multiplication is performed on the context vector of each word mask and the word vector parameter matrix to obtain the relevance between the context vector of the word mask and each word vector in the word vector parameter matrix, thereby obtaining a probability value of the word mask corresponding to each word vector in the vocabulary; each probability value represents the probability that the word mask corresponds to one word vector.
In this implementation, the context vector of the word mask is multiplied by the word vector parameter matrix, the obtained probability values are normalized, and for example, based on the normalized probability values, the word vector with the highest probability value may be selected as the word vector corresponding to the word mask, thereby determining the word vector corresponding to the word mask.
Optionally, in a possible implementation of this embodiment, the word vector parameter matrix in 104 may he configured as a pre-trained word vector parameter matrix, or an initialized word vector parameter matrix (i.e., an untrained word vector parameter matrix or a word vector parameter matrix which is not trained completely), the dimension of the word vector parameter matrix may be [dimension of word vector, size of vocabulary], and the size of the vocabulary is the number of the words contained in the vocabulary, which is not limited in this embodiment of the present application.
When the word vector parameter matrix is a pre-trained word vector parameter matrix, the training speed of the language model may be expedited, thereby improving the training efficiency.
In a specific implementation, when the word vector parameter matrix in 104 is an initialized word vector parameter matrix, in 105, the language model and the initialized word vector parameter matrix may be trained jointly based on the word vector corresponding to each word mask until the preset training completion condition is met; for example, the method according to the embodiment of the present application is executed using a plurality of sample text language materials, the words replaced with the word masks in the plurality of sample text language materials include a plurality of words (which may be partial or all words) in the vocabulary, and based on the above-mentioned embodiment, after the plurality of normalized probability values of each word mask corresponding to the plurality of word vectors are obtained, with maximization of the normalized probability values of all the word masks participating in the training process as a target, the word vector of each of all the word masks and representation of each word vector in the word vector parameter matrix are determined to obtain the trained word vector parameter matrix, the word vector of each word in the vocabulary may be represented accurately, and therefore, the trained word vector parameter matrix serves as an overall word vector.
In this implementation, when the initialized word vector parameter matrix is adopted, the joint training process of the language model and the initialized word vector parameter matrix may expedite the convergence speed of the language model and the word vector, thereby improving the training effect.
Optionally, in a possible implementation of this embodiment, the language model in the above-mentioned embodiment of the present application may be configured as any language model, for example, an ERNIE model.
The ERNIE model may learn the semantic representation of a complete concept by modeling prior semantic knowledge, such as entity concepts in mass data, or the like, and is pre-trained by masking semantic units, such as words and the entity concepts, or the like, such that the representation of semantic knowledge units by the ERNIE model is closer to the real world, and the ERNIE model directly models the prior semantic knowledge units while performing the modeling process based on character feature input, and has a strong semantic representation capability. In this embodiment, the ERNIE model is used as the language model, and the strong semantic representation capability of the ERNIE model may be used to model the words, the entities and the entity relationships in the mass data and learn the semantic knowledge of the real world, thereby enhancing the semantic representation capability of the model; for example, by learning the representation of the words and the entities, the ERNIE model is able to model the relationship between “(ha)(er)” and “(hei) (long)(jiang)” and learns “(ha)(er)(bin)(shi)(hei)(long)(jiang)(de)(sheng) (hui) (which means in English: Harbin is the provincial capital of Heilongjiang” and “(ha)(er) (bin)”(bing)(xue)(cheng)(shi) (which means in English: Harbin is an icy and snowy city)”.
On the basis of the above-mentioned embodiment, after the trained language model is obtained when the preset training completion condition is met, the language model may be further optimized with a supervised NLP task, so as to further improve the prediction performance of the language model in the NLP task.
In the second embodiment, the optimization of the language model with the supervised NLP task may include the following steps:
201: performing the NLP task with the trained language model to obtain a processing result.
Optionally, in a possible implementation of this embodiment, the NLP task may be any one or more of NLP tasks, such as classification, matching, sequence annotation, or the like, which is not particularly limited in this embodiment. Correspondingly, the processing result is a processing result of the specific NLP task, for example, a classification result, a matching result, a sequence annotation result, or the like.
Optionally, in a possible implementation of this embodiment, in 201, the NLP task may be performed specifically by using the trained language model in conjunction with other network models for implementing classification, matching and sequence annotation, for example, a convolutional neural network (CNN), a long short term memory (LSTM) model and a bag of word (BOW) model, so as to obtain the processing result; for example, the other network models for implementing classification, matching and sequence annotation may perform these processing tasks based on the output of the language model, so as to obtain the corresponding classification result, the corresponding matching result, the corresponding sequence annotation result and other processing results.
202: according to a difference between the processing result and annotated result information, finely tuning parameter values in the language model until a preset condition is met, for example, the difference between the processing result and the annotated result information being smaller than a preset difference, and/or the number of training times of the language model reaching a preset number of times.
The annotated result information is a correct processing result which is manually annotated in advance for the NLP task to be performed.
In this embodiment, since the word vector parameter matrix is not required, the language model may be further optimized with the NLP task with supervision data (i.e., the annotated result information) without changing the overall structure of the language model, thus improving the prediction performance of the language model, and facilitating iterative optimization of the language model according to each NLP task.
It should be noted that for simplicity of description, the above-mentioned embodiments of the method are described as combinations of a series of acts, but those skilled in the art should understand that the present application is not limited by the described order of acts, as some steps may be performed in other orders or simultaneously according to the present application. Further, those skilled in the art should also understand that the embodiments described in this specification are preferred embodiments and that acts and modules referred to are not necessary for the present application.
In the above-mentioned embodiments, the descriptions of the respective embodiments have respective emphasis, and for parts that are not described in detail in a certain embodiment, reference may be made to the related descriptions of other embodiments.
It should be noted that part or all of execution subjects or the training apparatus for the language model according to this embodiment may be configured as an application located at a local terminal, or a functional unit, such as a plug-in or software development kit (SDK) provided in the application located at the local terminal, or the like, or a processing engine located at a network-side server, which is not particularly limited in this embodiment.
It may be understood that the application may he configured as a native application (nativeApp) installed at the terminal, or a web application (webApp) of a browser at the terminal, which is not limited in this embodiment.
In this embodiment, semantic information representation with greater granularity is introduced, the word vectors contain richer semantic information representation compared with character vectors, and the word vectors are modeled directly based on contexts, thus enhancing the process of modeling the word meaning information by the language model and the capacity of the language model to learn the word meaning information.
In addition, with the technical solution of the present application, since the word in the sample text language material is replaced with the word mask to train the language model, the information leakage risk possibly caused by character-based full word coverage may be avoided effectively.
In addition, with the technical solution of the present application, the prediction performance of the language model may be improved effectively.
Optionally, referring to
Optionally, in a possible implementation of this embodiment, the word vector parameter matrix 402 may be configured as a pre-trained word vector parameter matrix, or an initialized word vector parameter matrix (i.e., an untrained word vector parameter matrix or a word vector parameter matrix which is not trained completely), which is not limited in this embodiment of the present application.
In an implementation, when the word vector parameter matrix 402 is configured as the initialized word vector parameter matrix, the training unit 305 is specifically configured to train the language model and the initialized word vector parameter matrix based on the word vector corresponding to each word mask until the preset training completion condition is met.
Optionally, in a possible implementation of this embodiment, the language model 303 may be configured as any language model, for example, an ERNIE model.
Optionally, in a possible implementation of this embodiment, the language model 303 may be further configured to perform a natural language processing task after the preset training completion condition is met, so as to obtain a processing result. Correspondingly, referring to
It should be noted that the method according to the embodiments corresponding to
According to embodiments of the present application, there are also provided an electronic device and a non-transitory computer-readable storage medium storing computer instructions.
As shown in
The memory 502 is configured as the non-transitory computer-readable storage medium according to the present application. The memory stores instructions executable by the at least one processor to cause the at least one processor to perform a method for training a language model according to the present application. The non-transitory computer-readable storage medium according to the present application stores computer instructions for causing a computer to perform the method for training a language model according to the present application.
The memory 502 which is a non-transitory computer-readable storage medium may be configured to store non-transitory software programs, non-transitory computer executable programs and units, such as program instructions/units corresponding to the method for training a language model according to the embodiments of the present application (for example, the pre-training unit 301, the replacing unit 302, the language model 303, the determining unit 304 and the training unit 305 shown in
The memory 502 may include a program storage area and a data storage area, wherein the program storage area may store an operating system and an application program required for at least one function; the data storage area may store data created according to use of the electronic device for implementing the method for training a language model according to the embodiments of the present application, or the like. Furthermore, the memory 502 may include a high-speed random access memory, or a non-transitory memory, such as at least one magnetic disk storage device, a flash memory device, or other non-transitory solid state storage devices. In some embodiments, optionally, the memory 502 may include memories remote from the processor 501, and such remote memories may be connected via a network to the electronic device for implementing the method for training a language model according to the embodiments of the present application. Examples of such a network include, but are not limited to, the Internet, intranets, local area networks, mobile communication networks, and combinations thereof.
The electronic device for the method for training a language model may further include an input device 503 and an output device 504. The processor 501, the memory 502, the input device 503 and the output device 504 may be connected by a bus or other means, and
The input device 503 may receive input numeric or character information and generate key signal input related to user settings and function control of the electronic device for implementing the method for training a language model according to the embodiments of the present application, such as a touch screen, a keypad, a mouse, a track pad, a touch pad, a pointing stick, one or more mouse buttons, a trackball a joystick, or the like. The output device 504 may include a display device, an auxiliary lighting device (for example, an LED) and a tactile feedback device (for example, a vibrating motor), or the like. The display device may include, but is not limited to, an LCD (liquid crystal display), an LED (light emitting diode) display, and a plasma display. In some implementations, the display device may be a touch screen.
Various implementations of the systems and technologies described here may be implemented in digital electronic circuitry, integrated circuitry, ASICs (application specific integrated circuits), computer hardware, firmware, software, and/or combinations thereof These various implementations may be implemented in one or more computer programs which are executable anchor interpretable on a programmable system including at least one programmable processor, and the programmable processor may be special or general, and may receive data and instructions from, and transmitting data and instructions to, a storage system, at least one input device, and at least one output device.
These computer programs (also known as programs, software, software applications, or codes) include machine instructions for a programmable processor, and may be implemented using high-level procedural and/or object-oriented programming languages, and/or assembly/machine languages. As used herein, the terms “machine-readable medium” and “computer-readable medium” refer to any computer program product, device and/or apparatus (for example, magnetic discs, optical disks, memories, PLDs (programmable logic devices)) for providing machine instructions and/or data to a programmable processor, including a machine readable medium which receives machine instructions as a machine readable signal. The term “machine readable signal” refers to any signal for providing machine instructions and/or data to a programmable processor.
To provide interaction with a user, the systems and technologies described here may be implemented on a computer having: a display device (for example, a CRT (cathode ray tube) or LCD (liquid crystal display) monitor) for displaying information to a user; and a keyboard and a pointing device (for example, a mouse or a trackball) by which a user may provide input to the computer. Other kinds of devices may also be used to provide interaction with a user; for example, feedback provided to a user may be any form of sensory feedback (for example, visual feedback, auditory feedback, or tactile feedback); and input from a user may be received in any form (including, acoustic, language or tactile input).
The systems and technologies described here may be implemented in a computing system (for example, as a data server) which includes a back-end component, or a computing system (for example, an application server) which includes a middleware component, or a computing system (for example, a user computer having a graphical user interface or a web browser through which a user may interact with an implementation of the systems and technologies described here) which includes a front-end component, or a computing system which includes any combination of such back-end, middleware, or front-end components. The components of the system may be interconnected through any form or medium of digital data communication (for example, a communication network). Examples of the communication network include: an LAN (local area network), a WAN (wide area network) and the Internet.
A computer system may include a client and a server. Generally, the client and the server are remote from each other and interact through the communication network. The relationship between the client and the server is generated by virtue of computer programs which are run on respective computers and have a client-server relationship to each other.
According to the technical solution of the embodiments of the present application, semantic information representation with greater granularity is introduced, the word vectors contain richer semantic information representation compared with character vectors, and the word vectors are modeled directly based on contexts, thus enhancing the process of modeling the word meaning information by the language model and the capacity of the language model to learn the word meaning information.
In addition, with the technical solution of the present application, since the word in the sample text language material is replaced with the word mask to train the language model, the information leakage risk possibly caused by character-based hill word coverage may be avoided effectively.
In addition, with the technical solution of the present application, the prediction performance of the language model may be improved effectively.
It should be understood that various fortes of the (lows shown above may be used and reordered, and steps may be added or deleted. For example, the steps described in the present application may be executed in parallel, sequentially, or in different orders, and are not limited herein as long as the desired results of the technical solution disclosed in the present application may be achieved.
The above-mentioned embodiments are not intended to limit the scope of the present application. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions may be made, depending on design requirements and other factors. Any modification, equivalent substitution and improvement made within the spirit and principle of the present application all should be included in the extent of protection of the present application.
Number | Date | Country | Kind |
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2020104797441 | May 2020 | CN | national |