Digital Space Control System, Digital Space Control Method, and Program
The digital space control system allows immediate three-dimensionalization and display of user-input text, addressing the limitation of requiring pre-included three-dimensional character data in existing technologies.
Patent Information
- Application Number
- JP2024120310
- Authority / Receiving Office
- JP · JP
- Patent Type
- Patents
- Current Assignee / Owner
- Filing Date
- 2024-07-25
- Publication Date
- 2025-07-01
- Estimated Expiration
- 2044-07-25
AI Technical Summary
Existing technologies cannot immediately stereoscopicize and display text input by a user without pre-including three-dimensional character data.
A digital space control system with a text acquisition unit, an object generation unit, and a digital space control unit that enables immediate three-dimensionalization and display of input text as a 3D object in a digital space.
Enables immediate three-dimensional display of user-input text without requiring pre-included three-dimensional character data, offering high flexibility and freedom in character string display.
Smart Images

Figure 0007700939000001_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to a digital space control system, a digital space control method, and a program.
Background Art
[0002] There is known a technique of demodulating a stereoscopic video signal including stereoscopic character data in a modulated form, extracting the stereoscopic character data, and displaying a stereoscopic video including stereoscopic characters using the stereoscopic video signal (see, for example, Patent Document 1).
Prior Art Documents
Patent Documents
[0003]
Patent Document 1
Summary of the Invention
Problems to be Solved by the Invention
[0004] In Patent Document 1, when displaying three-dimensional characters, it is necessary to include the three-dimensional character data in the three-dimensional video signal in advance. For this reason, for example, it is not possible to immediately stereoscopicize and display text in response to text input by a user.
[0005] In view of the above problems, an object of the present invention is to enable immediate stereoscopicization and display of input text.
Means for Solving the Problems
[0006] One aspect of the present invention for solving the above-described problems is a digital space control system including a text acquisition unit that acquires unit text consisting of one or more texts input by an operation performed on a user terminal, an object generation unit that generates a single text object in which each of the one or more texts included in the unit text acquired by the text acquisition unit is three-dimensionalized, and a digital space control unit that causes the text object generated by the object generation unit to appear in a digital space.
[0007] One aspect of the present invention is a digital space control method in a digital space control system, including a text acquisition step in which a text acquisition unit acquires unit text consisting of one or more texts input by an operation performed on a user terminal, an object generation step in which an object generation unit generates a single text object in which each of the one or more texts included in the unit text acquired by the text acquisition unit is three-dimensionalized, and a digital space control step in which a digital space control unit causes the text object generated by the object generation unit to appear in a digital space.
[0008] One aspect of the present invention is a program for causing a computer in a digital space control system to function as a text acquisition unit that acquires unit text consisting of one or more texts input by an operation performed on a user terminal, an object generation unit that generates a single text object in which each of the one or more texts included in the unit text acquired by the text acquisition unit is three-dimensionalized, and a digital space control unit that causes the text object generated by the object generation unit to appear in a digital space.
Advantages of the Invention
[0009] According to the present invention, an effect is obtained in that the input text can be immediately three-dimensionalized and displayed.
Brief Description of the Drawings
[0010]
Figure 1
Figure 2
Figure 3
Figure 4
Figure 5
Figure 6
Figure 7
Figure 8
Embodiments for Carrying Out the Invention
[0011] FIG. 1 shows an overall configuration example of the digital space control system in this embodiment. The digital space control system of this embodiment includes a digital space control device 100 and a user terminal 200. The digital space control device 100 and the user terminal 200 are communicably connected via a network.
[0012] The digital space control device 100 provides a metaverse as a digital space. The user can cause the user terminal 200 owned by the user to access the digital space control device 100, and thereby display the metaverse on the user terminal 200. The user can actuate an avatar corresponding to himself / herself in the displayed metaverse.
[0013] In the digital space control system of this embodiment, a user who utilizes the metaverse can operate the user terminal 200 to input text as a message. The text input by the user is rendered as a three-dimensional (3D) object and is displayed so as to appear in the metaverse. In the following description, the 3D text object that appears in the metaverse will also be referred to as a 3D text object.
[0014] Referring to FIGS. 2 to 4, an example of the form of the 3D text object that appears in the metaverse will be described. FIG. 2 shows an example of the screen of the metaverse displayed on the user terminal 200 corresponding to one user. In the metaverse displayed as shown in the figure, there is an avatar AVT corresponding to the user. The avatar AVT can move within the metaverse and change the direction in which the line of sight is directed (line-of-sight direction) according to the operation of the user on the user terminal 200. In the figure, the avatar AVT corresponding to the user is positioned such that the line-of-sight direction is directed towards the front on the back side of the metaverse. By positioning the avatar AVT in this way, the line-of-sight direction of the avatar AVT is made the same as the line-of-sight direction in which the user observes the metaverse through the screen.
[0015] Also, in the screen of the metaverse in the figure, a text operation area AR is arranged facing the user at the center on the front side. The text operation area AR is an area for performing operations related to the appearance of the 3D text object in the metaverse. The text operation area AR may be displayed so as to switch from a text input declaration button (not shown) arranged on the screen of the metaverse, for example, in response to the user operating the text input declaration button.
[0016] When the user attempts to make a 3D text object appear in the metaverse, they enter any one or more texts (unit texts) into the input box BX in the text operation area AR. Here, if the user wishes to erase the text entered in the input box BX, they operate the close button BT2 in the text operation area AR. In response to the operation of the close button BT2, the text operation area AR that has been displayed until now closes and switches to the display of the text input declaration button. Even when the display switches to the text input declaration button, the text entered in the input box BX may remain without being erased. In this case, the text previously entered is displayed in the input box BX of the text operation area AR redisplayed when the text input declaration button is operated again. By leaving the previously entered text without being erased in this way, the user does not need to perform the operation of re - entering the text from the first character. Then, after the user enters the unit text in the input box BX and operates the send button BT1, the unit text entered by the user appears as a 3D text object in the metaverse as shown by the transition from Figure 2 to Figure 3.
[0017] As an example, first, as shown in Figure 3, the 3D text object appears floating at the position in front of the user's avatar AVT (appearance position) as seen by the user. In Figure 3, each text (character) forming the unit text "こんにちは" entered by the user appears in a 3D state and is arranged in the order of the character string "こんにちは" from top to bottom in the vertical direction. Note that the arrangement pattern of the character string as the unit text may be, for example, in the horizontal direction or the diagonal direction, etc., and is not particularly limited. The 3D text object that appears at the appearance position as described above may move along a predetermined trajectory. Specifically, the 3D text object may use the front side in the direction that the avatar AVT is facing (which may be the direction that the front of the avatar AVT's body is facing or the direction of the avatar AVT's line of sight) as the appearance position, and move from the appearance position to the back side of the metaverse along the direction that the avatar AVT is facing. Also, for example, the moving speed of the 3D text object in the metaverse may be set according to the user's operation when inputting unit text. Alternatively, regardless of the position and orientation of the avatar AVT, in the indoor space displayed corresponding to the user's viewpoint, the 3D text object may be displayed as moving from the front side to the back side. Also, when the 3D text object is moving, each text (character) forming the 3D text object may be given movements such as swaying or rotating, size and shape changes such as stretching or shrinking, and color changes.
[0018] When the metaverse is an indoor space as shown in Figure 3, by the 3D text object moving to the back side of the metaverse as described above, the 3D text object may be allowed to contact an object (structures such as walls and pillars, other objects existing in the metaverse, etc.) in the indoor space in the metaverse at a certain timing. When contacting an object in the indoor space in this way, the 3D text object may be made to change its moving direction so as to reflect from the contacted object.
[0019] Also, in the metaverse, a plurality of 3D text objects respectively presented by a plurality of users may exist simultaneously. In this case, a plurality of users using the metaverse can communicate like chatting by presenting the 3D objects of the unit text input by themselves to each other.
[0020] Furthermore, in the metaverse, it may be allowed for multiple moving 3D text objects to come into contact with each other. When multiple 3D text objects come into contact in this way, each of the contacting 3D text objects may change its moving direction so as to reflect according to its previous moving direction and the direction from which the other 3D object has come, etc.
[0021] The 3D text object that appears in the metaverse may be made to disappear from the metaverse when a predetermined condition is satisfied. As an example, the 3D text object that appears in the metaverse may disappear when a predetermined time has elapsed. Also, the predetermined time in this case may be changed according to the number of characters of the unit text forming the 3D text object, etc.
[0022] Also, the 3D text object may be made to disappear after falling from a floating state to the floor surface. At this time, as shown in FIG. 4, the 3D text object may be made to disappear after being in a state of being stacked with each text (character) collapsing from a floating state.
[0023] Also, the 3D text object that appears in the metaverse may be made to disappear when the length (moving distance) of the trajectory moved in the metaverse becomes a certain length or more.
[0024] Also, the 3D text object may be made to disappear triggered by the contact of multiple 3D text objects with each other as described above. In this case, for example, all of the multiple contacting 3D text objects may disappear, or a part of them may disappear. As a case where a part disappears, for example, the 3D text object that has existed in the metaverse for the longest time among the multiple contacting 3D text objects may be made to disappear.
[0025] In this way, in this embodiment, the unit text input by the user can be immediately rendered as a 3D object and displayed in the metaverse. In this embodiment, the display of such 3D text objects can be easily performed by the user operating their own user terminal 200. Also, in the case of this embodiment, there is no need to prepare three-dimensional character data in advance, and since the unit text arbitrarily input by the user can be rendered three-dimensionally, there is a high degree of freedom in the character string of the 3D text object to be displayed.
[0026] Referring to FIG. 5, a hardware configuration example of the digital space control device 100 will be described. The digital space control device 100 in the figure includes a communication device 1001, a ROM (Read Only Memory) 1002, a RAM (Random Access Memory) 1003, a storage 1004, a CPU (Central Processing Unit) 1005, and a GPU (Graphics Processing Unit) 1006. The communication device 1001, ROM 1002, RAM 1003, storage 1004, CPU 1005, and GPU 1006 are connected by a bus 1007.
[0027] The communication device 1001 is a device corresponding to communication via a network. The ROM 1002 stores non-rewritable data. The RAM 1003 temporarily stores data used for operations executed by the CPU 1005. The storage 1004 is, for example, an HDD (Hard Disc Drive) or an SSD (Solid State Drive), and stores various types of data including, for example, program data. The CPU 1005 executes operations corresponding to various controls and processes by executing the programs stored in the storage 1004. The GPU 1006 executes processes related to image processing. Note that a function equivalent to that of the digital space control device 100 may be obtained by a plurality of network terminals distributed so as to be able to execute a transaction corresponding to the blockchain.
[0028] FIG. 6 shows a functional configuration example of the digital space control device 100. The functions of the digital space control device 100 in the figure are realized by a CPU (Central Processing Unit) provided in the digital space control device 100 executing a program. The digital space control device 100 in the figure includes a communication unit 101, a control unit 102, and a storage unit 103. The communication unit 101 communicates with the user terminal 200 via a network.
[0029] The control unit 102 executes various controls in the digital space control device 100. The control unit 102 in the figure includes a text acquisition unit 121, an object generation unit 122, and a digital space control unit 123.
[0030] The text acquisition unit 121 acquires unit text input by an operation on a text operation area AR in the metaverse displayed on the user terminal 200.
[0031] The object generation unit 122 generates a 3D text object by rendering each text (character) included in the unit text acquired by the text acquisition unit 121.
[0032] The digital space control unit 123 executes control related to the construction of the metaverse environment. As control related to the construction of the metaverse environment, the digital space control unit 123 may cause the 3D text object generated by the object generation unit 122 to appear in the metaverse, and control the movement, motion, size / shape change, color change, disappearance, etc. of the appeared 3D text object.
[0033] The storage unit 103 stores various types of information corresponding to the digital space control device 100. The storage unit 103 includes a digital space configuration information storage unit 131 and an avatar information storage unit 132.
[0034] The digital space configuration information storage unit 131 stores digital space configuration information. The digital space configuration information may include data for reproducing, for example, the walls, objects, acoustics, etc. of the indoor space as illustrated in FIGS. 2 to 4.
[0035] The avatar information storage unit 132 stores avatar information regarding the avatar AVT that the user uses as their alter ego. The avatar information storage unit 132 may store avatar information in correspondence with each user. The avatar information corresponding to one user may have a structure in which a combination of the avatar ID of the corresponding avatar and the avatar configuration data is associated with the user ID. The avatar configuration data may be, for example, data indicating a combination of parts that make up an object as the corresponding avatar. Further, the avatar information may also include the user name of the user specified by the user ID. The user name is input, for example, when the user logs in to the metaverse of the present embodiment.
[0036] Note that a plurality of avatars can be set corresponding to one user, and it may be possible for the user to cause the selected avatar among the plurality of avatars to exist in the metaverse. In this case, the avatar information corresponding to one user may store a combination of the avatar ID and the avatar configuration data for each of the plurality of set avatars.
[0037] Referring to FIG. 7, a functional configuration example of the user terminal 200 will be described. The hardware configuration of the user terminal 200 may include a communication device, a ROM, a RAM, a storage, a CPU (and a GPU) according to FIG. 5, and may include input devices such as buttons, a keyboard, a touch panel, etc. and output devices such as display and sound output. Further, the user terminal 200 may include a camera corresponding to a code reader function for reading a code symbol such as a two-dimensional code.
[0038] The user terminal 200 shown in FIG. 7 includes a communication unit 201, an operation unit 202, a display unit 203, a control unit 204, and a storage unit 205. The communication unit 201 is communicably connected to the digital space control device 100 via a network.
[0039] The operation unit 202 includes, for example, hardware devices such as a touch panel, keys, and buttons, receives a user's operation, and outputs operation information corresponding to the received operation to the control unit 204. Further, the operation unit 202 may be capable of voice operations according to the voice uttered by the user.
[0040] The display unit 203 includes, for example, a display device such as a touch panel as hardware, and displays an image under the control of the control unit 204.
[0041] The control unit 204 executes various controls in the user terminal 200.
[0042] The storage unit 205 stores, for example, programs executed by a CPU, GPU, etc. included in the user terminal 200, as well as information related to the user terminal 200.
[0043] Referring to the flowchart of FIG. 8, an example of a processing procedure executed by the digital space control system of the present embodiment in relation to the display of 3D text objects in the metaverse will be described. First, an example of a processing procedure executed by the user terminal 200 will be described.
[0044] Step S100: A user who wants to cause a 3D text object to appear in the metaverse performs an operation of inputting unit text consisting of any one or more character strings to an input box BX in a text operation area AR (unit text input operation). The control unit 204 of the user terminal 200 receives the unit text input operation performed by the user.
[0045] Step S102: The user inputs unit text into the input box BX, and then performs an operation to confirm the input unit text as unit text to be displayed as a 3D text object in the metaverse (unit text confirmation operation). The unit text confirmation operation may be an operation on the send button BT1 in the text operation area AR. The control unit 204 receives the unit text confirmation operation performed by the user.
[0046] Step S104: In response to receiving the unit text confirmation operation, the control unit 204 transmits the unit text input by the unit text input operation received in step S100 to the digital space control device 100.
[0047] Next, a description will be given of an example of the processing procedure executed by the digital space control device 100. Step S200: In the digital space control device 100, the text acquisition unit 121 acquires the unit text transmitted from the user terminal 200 in step S104.
[0048] Step S202: The object generation unit 122 generates a 3D text object by performing rendering to 3Dize the text (characters) for each unit text acquired in step S200.
[0049] Step S204: Based on the position and line-of-sight direction of the corresponding user's avatar AVT in the metaverse, the digital space control unit 123 sets the appearance position and trajectory of the 3D text object generated in step S202 in the metaverse.
[0050] Step S206: The digital space control unit 123 causes the 3D text object generated in step S202 to appear at the appearance position set in step S204. The digital space control unit 123 starts control to move the 3D text object that has appeared at the appearance position along the trajectory set in step S204.
[0051] Step S208: The digital space control unit 123 waits for a predetermined time to elapse after causing the 3D text object to appear in step S206.
[0052] Step S210: If it is determined in step S208 that the predetermined time has not elapsed, the digital space control unit 123 determines whether the 3D text object whose movement was started in step S206 has come into contact with other objects in the metaverse. If it is determined that there is no contact with other objects, the process returns to step S208.
[0053] Step S212: If it is determined in step S210 that there has been contact with other objects, the digital space control unit 123 changes the trajectory of the 3D text object. At this time, the digital space control unit 123 may calculate the changed path using predetermined parameters such as the position, shape, moving direction, and hardness of the contacted object. After the process of step S212, the process returns to step S208.
[0054] Step S214: If it is determined in step S208 that the predetermined time has elapsed, the digital space control unit 123 causes the 3D text object that appeared in step S206 to disappear from the metaverse.
[0055] <Supplementary Note> (1) One aspect of this embodiment is a digital space control system including a text acquisition unit that acquires unit texts consisting of one or more texts input by an operation performed on a user terminal, an object generation unit that generates a single 3D text object by three-dimensionalizing each of the one or more texts included in the unit texts acquired by the text acquisition unit, and a digital space control unit that causes the text object generated by the object generation unit to appear in the digital space.
[0056] (2) One aspect of this embodiment is the digital space control system described in (1), wherein the digital space control unit may impart movement to a text object presented in the digital space.
[0057] (3) One aspect of this embodiment is the digital space control system described in (1) or (2), wherein the digital space control unit may set the appearance position of the text object and the trajectory of movement starting from the appearance position based on the position where an avatar exists in the digital space and the direction in which the avatar is facing, as the avatar of the user who performed the operation of inputting text.
[0058] (4) One aspect of this embodiment is the digital space control system described in (3), wherein the digital space control unit may set the appearance position on the front side in the direction in which the avatar is facing and the trajectory of movement along the direction in which the avatar is facing starting from the appearance position.
[0059] (5) One aspect of this embodiment is the digital space control system described in (1) or (2), wherein the digital space control unit may present the text object on the front side of the displayed digital space along the viewing point of the user observing the displayed digital space, and display it so as to move it to the back side of the displayed digital space.
[0060] (6) One aspect of this embodiment is the digital space control system described in any one of (1) to (5), wherein the digital space control unit may cause the text object to disappear in response to a predetermined condition being satisfied after the text object appears in the digital space.
[0061] (7) One aspect of this embodiment is the digital space control system described in (4), wherein when the digital space control unit causes the text object composed of a plurality of texts to disappear, it may display the plurality of texts in a state of falling onto and stacking on the floor surface of the digital space.
[0062] (8) One aspect of this embodiment is the digital space control system described in (1) to (5), wherein the digital space control unit may change the trajectory of the text object when the text object appearing in the digital space comes into contact with another object.
[0063] (9) One aspect of this embodiment is a digital space control method in a digital space control system, including a text acquisition step in which a text acquisition unit acquires a unit text composed of one or more texts input by an operation performed on a user terminal, an object generation step in which an object generation unit generates a single text object in which each of the one or more texts included in the unit text acquired by the text acquisition unit is three-dimensionalized, and a digital space control step in which a digital space control unit causes the text object generated by the object generation unit to appear in the digital space.
[0064] (10) One aspect of this embodiment is a program for causing a computer in a digital space control system to function as a text acquisition unit that acquires a unit text composed of one or more texts input by an operation performed on a user terminal, an object generation unit that generates a single text object in which each of the one or more texts included in the unit text acquired by the text acquisition unit is three-dimensionalized, and a digital space control unit that causes the text object generated by the object generation unit to appear in the digital space.
[0065] Note that a program for realizing functions such as the above-described digital space control device 100 and user terminal 200 may be recorded on a computer-readable recording medium, and the program recorded on this recording medium may be read into a computer system and executed to perform processing such as the above-described digital space control device 100 and user terminal 200. Here, "reading and executing the program recorded on the recording medium by the computer system" includes installing the program in the computer system. The "computer system" referred to here shall include hardware such as an OS and peripheral devices. Further, the "computer system" may include a plurality of computer devices connected via a network including a communication line such as the Internet, WAN, LAN, or dedicated line. Also, the "computer-readable recording medium" refers to a portable medium such as a flexible disk, magneto-optical disk, ROM, CD-ROM, or a storage device such as an HDD or SDD built into a computer system. Thus, the recording medium storing the program may be a non-transitory recording medium such as a CD-ROM. The recording medium also includes an internal or external recording medium provided so as to be accessible from a distribution server for distributing the program. The code of the program stored in the recording medium of the distribution server may be different from the code of the program in a form executable by the terminal device. That is, as long as it can be downloaded from the distribution server and installed in a form executable by the terminal device, the form stored in the distribution server does not matter. Note that the program may be divided into a plurality of parts, downloaded at different timings, and then combined by the terminal device, or the distribution servers for distributing the respective divided programs may be different. Furthermore, the "computer-readable recording medium" shall also include a volatile memory (RAM) inside a computer system serving as a server or client when the program is transmitted via a network, which holds the program for a certain period of time. Also, the above program may be for realizing a part of the above-described functions.Furthermore, it may be a so-called differential file (differential program) that can be realized in combination with a program already recorded in a computer system for the above-described functions.
Explanation of Signs
[0066] 100 Digital space control device, 101 Communication unit, 102 Control unit, 103 Storage unit, 121 Text acquisition unit, 122 Object generation unit, 123 Digital space control unit, 131 Digital space configuration information storage unit, 132 Avatar information storage unit, 200 User terminal
Claims
1. a text acquisition unit that acquires a unit text including one or more pieces of input text in response to an operation of inputting one or more pieces of text into a user terminal; an object generating unit that generates a text object as a collection of one or more individual objects obtained by three-dimensionally converting one or more pieces of text included in the unit text acquired by the text acquiring unit; a digital space control unit that causes the text object generated by the object generation unit to appear in a floating state in a digital space, and that causes the text object to disappear in response to a predetermined condition being satisfied after the text object appears; The digital space control unit, when erasing the text object consisting of a plurality of individual objects corresponding to each of a plurality of texts that are individually three-dimensionalized, displays the plurality of individual objects as if they are falling onto a floor surface of the digital space in a state of collapsing. Digital spatial control system.
2. The digital space control unit sets an appearance position of the floating text object and a movement trajectory starting from the appearance position, based on a position in the digital space of an avatar of the user who performed the operation of inputting text and a direction in which the avatar is facing. The digital spatial control system according to claim 1 .
3. The digital space control unit sets an appearance position on the near side of the direction in which the avatar is facing with respect to the floating text object, and a movement trajectory along the direction in which the avatar is facing, starting from the appearance position. The digital spatial control system according to claim 2.
4. The digital space control unit makes the text object appear in a floating state at the front side of the displayed digital space along the viewpoint of a user observing the displayed digital space, and displays the text object in a floating state as it moves to the back side of the displayed digital space. A digital spatial control system according to any one of claims 1 to 3.
5. The digital space control unit displays the plurality of individual objects so as to fall onto a floor surface of the digital space and pile up. A digital spatial control system according to any one of claims 1 to 3.
6. The digital space control unit changes a trajectory of a text object in response to the text object appearing in the digital space coming into contact with another object. A digital spatial control system according to any one of claims 1 to 3.
7. A digital space control method in a digital space control system, comprising: a text acquisition step in which a text acquisition unit acquires a unit text including one or more pieces of input text in response to an operation of inputting one or more pieces of text into a user terminal; an object generating step in which an object generating unit generates a text object as a collection of one or more individual objects obtained by three-dimensionally rendering one or more pieces of text included in the unit text acquired by the text acquiring unit; a digital space control step of causing the text object generated by the object generation unit to appear in a floating state in the digital space, and causing the text object to disappear in response to a predetermined condition being satisfied after the text object appears, In the digital space control step, when the text object is made to disappear by a plurality of individual objects corresponding to each of a plurality of texts that are individually three-dimensionalized, the plurality of individual objects are displayed as falling in a state of collapsing onto a floor surface of the digital space. Digital spatial control method.
8. Computers in digital spatial control systems, a text acquisition unit that acquires a unit text including one or more pieces of input text in response to an operation of inputting one or more pieces of text into a user terminal; an object generating unit that generates a text object as a collection of one or more individual objects obtained by three-dimensionally converting one or more pieces of text included in the unit text acquired by the text acquiring unit; A digital space control unit that makes the text object generated by the object generation unit appear in a floating state in a digital space, and makes the text object disappear when a predetermined condition is satisfied after the text object appears, and when the text object is made up of a plurality of individual objects corresponding to each of a plurality of texts that have been individually three-dimensionalized, the digital space control unit displays the plurality of individual objects falling in a state of collapsing onto the floor of the digital space. A program to function as a
Citation Information
Patent Citations
Stereoscopic video display device
JP1999289555A
Game device and program
JP2021016406A
Interactive processing method, device, electronic device and computer program for virtual tools
JP2023517115A
Information processing system, information processing method and information processing program
JP2024012541A
Item control method and device therefor, storage medium as well as electronic apparatus
JP2024062977A