Abstract: An electronic device and an operation method thereof are provided. The electronic device includes a communication interface, a memory storing one or more instructions, and a processor configured to execute the one or more instructions stored in the memory to recognize a program associated with content to be displayed, request, through the communication interface, a server for information about a chat room corresponding to a program identity (ID) of the recognized program, and output, based on the information about the chat room being obtained from the server in response to the request, a user interface to allow control as to whether to execute the chat room corresponding to the program ID of the recognized program while the content is being displayed.

Abstract: A method of operating a display apparatus includes: obtaining display apparatus state information indicating data processing performance of the display apparatus, transmitting the display apparatus state information to a server that provides a chat service, receiving chat messages transmitted from the server according to a message throughput determined based on the display apparatus state information, and outputting the received chat messages.

Abstract: Provided are a display apparatus and a method for providing a chat service for video content. A processor of the display apparatus receives video content. In response to requesting a chat room corresponding to the video content based on a user account, the processor receives chat messages and displays the received chat messages of the first chat room together with the video content on the display screen. In response to a chat room to which the user account belongs being changed from the first chat room to a second chat room based on an amount of chat messages of the user account transmitted to the chat server, the processor receives chat messages of the second chat room from the chat server, and displays the received chat messages of the second chat room through the display screen.

Abstract: An electronic device may include a first structure, a second structure, a flexible display, at least one sensor, and at least one processor, wherein the at least one processor may be configured to: obtain information on a state of the first structure with respect to the second structure via the at least one sensor; detect a touch input via the at least one sensor; based on the information on the state of the first structure with respect to the second structure, identify a portion of the flexible display where the touch input is detected between a first portion visually exposed to an outside and a second portion accommodated in an inside of the second structure in the flexible display; and based on the identified portion being the second portion, perform a function associated with a screen displayed via the first portion, based on the touch input.

Abstract: Provided is a hydraulic machine. A pump pressurizes fluid using power provided by a power source. An actuator works using the pressurized fluid from the pump. A recovery part recovers energy from fluid discharged from the actuator. A first operator input device receives a desired input from an operator to select an eco-mode or a boost mode. The recovery part includes an accumulator storing hydraulic energy by receiving the fluid discharged from the actuator and an assist unit assisting the power source using the hydraulic energy stored in the accumulator. The controller controls the pump such that output power of the pump does not exceed Plmax when the eco-mode is selected or the assist unit does not assist the power source and that the output power does not exceed P2max when the boost mode is selected and the assist unit assists the power source, where Plmax < P2max.

Abstract: A substrate-cleaning apparatus may include a tilting arm to which a roll brush and a motor are coupled, a support arm positioned on the tilting arm, a first spring and a second spring coupling the tilting arm to the support arm, a first air bag and a second air bag mounted between the tilting arm and the support arm, and a controller configured to adjust an internal pressure of each of the first air bag and the second air bag. The controller may adjust a difference in internal pressure between the first air bag and the second air bag to control the inclination of the roll brush, and may adjust the internal pressure of each of the first air bag and the second air bag to move the roll brush vertically.

Abstract: A hydraulic machine. A boom actuator includes a large chamber and a small chamber. A recovery unit receives fluid discharged from the large chamber and then recovers energy. A recovery line connects the large chamber and the recovery unit. An accumulator is connected to a first point on the recovery line. A discharge valve is disposed on the recovery line between the first point and the recovery unit. A first sensor measures a pressure in the accumulator. A controller controls opening and closing of the discharge valve. The controller performs anti-bouncing control of: determining a target pressure in the accumulator corresponding to a load pressure applied to fluid in the large chamber by a load according to a predetermined correspondence; and controlling the opening and closing of the discharge valve such that the pressure in the accumulator measured by the first sensor reaches the target pressure.

Abstract: A hydraulic machine is provided. A boom actuator includes a large chamber and a small chamber. A recovery unit receives fluid discharged from the large chamber and then recovers energy. A recovery line connects the large chamber and the recovery unit. An accumulator is connected to the recovery line. A jack-up assist line connects the accumulator and the small chamber. A jack-up assist valve is disposed on the jack-up assist line to block flow of fluid from the accumulator to the small chamber in a first position and allow the flow of fluid from the accumulator to the small chamber in a second position. A controller controls movement of the jack-up assist valve. The controller may determine whether or not the hydraulic machine is in a jack-up condition, and when the hydraulic machine is determined to be in the jack-up condition, moves the jack-up assist valve to the second position.

Abstract: Provided is a waveguide-type display device including a waveguide, an input coupler provided on the waveguide and configured to transmit an image to travel into the waveguide, an output coupler provided on the waveguide and configured to output the image traveling in the waveguide to an outside of the waveguide, and a field-of-view (FOV) expander configured to output an image having an expanded FOV by deflecting and outputting the image output from the output coupler in a certain direction based on polarization characteristics of the image.

Abstract: A hydraulic machine is provided. A boom actuator includes a large chamber and a small chamber. A recovery unit receives fluid discharged from the large chamber and then recovers energy. A recovery line connects the large chamber and the recovery unit. An accumulator is connected to the recovery line. A jack-up assist line connects the accumulator and the small chamber. A jack-up assist valve is disposed on the jack-up assist line to block flow of fluid from the accumulator to the small chamber in a first position and allow the flow of fluid from the accumulator to the small chamber in a second position. A controller controls movement of the jack-up assist valve. The controller may determine whether or not the hydraulic machine is in a jack-up condition, and when the hydraulic machine is determined to be in the jack-up condition, moves the jack-up assist valve to the second position.

Abstract: A hydraulic machine. A boom actuator includes a large chamber and a small chamber. A recovery unit receives fluid discharged from the large chamber and then recovers energy. A recovery line connects the large chamber and the recovery unit. An accumulator is connected to a first point on the recovery line. A discharge valve is disposed on the recovery line between the first point and the recovery unit. A first sensor measures a pressure in the accumulator. A controller controls opening and closing of the discharge valve. The controller performs anti-bouncing control of: determining a target pressure in the accumulator corresponding to a load pressure applied to fluid in the large chamber by a load according to a predetermined correspondence; and controlling the opening and closing of the discharge valve such that the pressure in the accumulator measured by the first sensor reaches the target pressure.

Abstract: Provided is a method of generating a hologram, the method including generating a kernel and a neural network configured to model an aberration of a holographic display device, obtaining second image data output from the neural network to which first image data obtained by propagating a first hologram based on the kernel is input, updating the kernel and the neural network based on comparing the second image data and predetermined image data, and generating a second hologram based on the kernel and the neural network.

Abstract: Provided are holographic display systems and methods for generating a hologram by compensating for aberrations of a holographic display device. The holographic display system may include a holographic display device and a hologram generating device. The hologram generating device may generate a hologram by propagating hologram segments, using kernels generated by modeling each aberration corresponding to each of hologram plane segments to compensate for aberrations.

Abstract: A holographic display with a spatial light modulator coupled to a pupil-replicating lightguide is disclosed. The spatial light modulator provides a light beam with spatially modulated amplitude and/or phase. The light beam is replicated by the pupil-replicating lightguide into a plurality of portions. The portions interfere at an exit pupil to provide an image for direct observation by a user. An eye-tracking system may be provided to determine the position of the user pupils, and the spatial modulation of the light beam may be adjusted accordingly to make sure that the optical interference of the beam portions at the eye pupils provides the required image.

Abstract: Provided is a multi-image display apparatus including an image forming device configured to form a first image, a first polarization plate configured to transmit a first polarization component of the first image provided from the image forming device, a second polarization plate configured to transmit a second polarization component of a second image that is provided from a path different from the first image, the second polarization component being different from the first polarization component, a screen configured to reflect and diffuse the first image, and transmit the second image, and a polarization selective lens configured to focus the first image having the first polarization component, and transmit the second image having the second polarization component without refraction.

Abstract: A hologram display device includes a light generator generating light, a spatial light modulator forming an interference pattern to interfere with the light, and a controller providing interference data to the spatial light modulator to form the interference pattern. The spatial light modulator includes a first area in which pixels are arranged in a first pattern, and a second area in which pixels are arranged in a second pattern. The controller includes a data generator generating first interference data for the first area and second interference data for the second area, a compensator generating first correction data based on the first interference data and second correction data by correcting the second interference data, and an output unit generating the interference data based on the first correction data and the second correction data.

Abstract: An apparatus for manufacturing a hologram includes a holographic optical element on which a first interference pattern of a first signal beam and a first reference beam is recorded and a second interference pattern of a second signal beam modulated by a Fourier lens and a second reference beam is recorded. Also, an apparatus for reconstructing a hologram by using the holographic optical element is provided.

Abstract: Provided is a multi-image display apparatus including an image forming device configured to form a first image, a first polarization plate configured to transmit a first polarization component of the first image provided from the image forming device, a second polarization plate configured to transmit a second polarization component of a second image that is provided from a path different from the first image, the second polarization component being different from the first polarization component, a screen configured to reflect and diffuse the first image, and transmit the second image, and a polarization selective lens configured to focus the first image having the first polarization component, and transmit the second image having the second polarization component without refraction.

Abstract: An optical apparatus and a near-eye display apparatus including the same are provided. The optical apparatus includes a display panel configured to form an image, a first polarization rotator configured to electrically control a light emitted from the display panel to have a first polarization state, a first ¼ wave plate configured to convert the first polarization state of a light transmitted from the first polarization rotator to a second polarization state, and an optical element group configured to display a first image having a first viewing angle and a second image having a second viewing angle that is greater than the first viewing angle based on the second polarization state of a light transmitted from the first ¼ wave plate.

Abstract: A display apparatus including a volume grating-based combiner is disclosed. The display apparatus includes: an image providing device; and a combiner, wherein the combiner includes a plurality of volume gratings configured to diffract light containing an image, which is emitted from the image providing device, each volume grating has a first surface and a second surface facing each other, and each volume grating is further configured to diffract light incident on the first surface and transmit therethrough light incident on the second surface without diffraction.