Abstract: Toilet paper with printed teaching aids provides printed teaching aids to help very young children learn the alphabet, colors, numbers, and simple arithmetic and reading lessons. The toilet paper may provide a range of age appropriate teaching aids, such as a roll of colors for toddlers, a roll of letters and numbers for preschoolers, a roll of simple reading words for first graders, and a roll of simple arithmetic and reading rhymes for second graders.

Abstract: Hook material cut into shapes, symbols, letters or words that are attached to loop pile-type commercial grade carpeting to convey spatial and directional non-verbal messages are disclosed. The hook material adheres to the loop pile-type commercial carpet and has the ability to be changed at any time without the use of adhesives or chemicals. The hook material may further possess a desired color and/or texture as may be desired for a particular application, including areas having heavy pedestrian traffic and/or to enhance child education.

Abstract: A source driver circuit is provided which includes a plurality of digital multi-spread (hereinafter referred to as “DMS”) blocks configured to generate DMS signals for controlling an output timing of a data signal to be transmitted to a display panel from a plurality of clocks which are delayed as much as a reference period one another. Each DMS block includes a plurality of sub blocks. Each of the sub blocks includes an enable signal generator and a delay unit. The enable signal generator generates an enable signal for outputting target DMS signals of the DMS signals using clocks selected from the plurality of clocks. The delay unit delays the DMS signals such that the DMS signals are sequentially delayed by the reference period.

Abstract: An image color enhancement method for a display is disclosed and comprises the steps of: S101: gathering tristimulus values of CIE1931 color space in light of all RGB combination of an image shown on the display, and computing a relative chrominance value and a relative luminance value; S102: obtaining a RGB triangle of color gamut of the display according to the chrominance value; S103: for a chromaticity point D1 which is relative to the RBG triangle of a RGB data, defining a relative saturation is S ? ? 1 = OD 1 OD ; S104: adopting a gain function to conduct gain computing for the relative saturation S1 and obtaining a gain saturation S2; S105: according to a formula OD2=OD*S2, obtaining the gain saturation S2 relative to the chrominance value D2 in the RGB triangle and the chrominance value D2 is located in the line OD; S106: computing the RGB data corresponding to the chrominance values D2 and obtaining the RGB data after saturation enhancement.

Abstract: Systems and methods for operating a display by dynamically determining a refresh rate for the display. In certain implementations, a processor determines a number of pixels having medium grayscale levels from a histogram for the image. If the number does not exceed a threshold, the processor sets a refresh rate for the display to a first refresh rate. In certain implementations, if the number exceeds a threshold, the processor may set the refresh rate for the display to a second refresh rate. Moreover, the first refresh rate may be lower than the second threshold. In some implementations, the image may be analyzed by subdividing the image into blocks and determining a refresh rate based on grayscale levels or distributions in the blocks. Based on the analysis of the blocks, a corresponding refresh rate may be selected.

Abstract: Display data is altered for a flexed portion of a flexible display. A stress amount (e.g., hinge angle) is detected for the affected region of the display. Based on the stress amount and location of the stress, a color mapping is changed to cause the affected portion to display as desired, for example to display consistently with other portions of the display. Viewing angle can be detected and used to further change the color mapping for the affected region. Changing the color mapping may be based on empirical data stored for known stresses for the display or similar displays.

Abstract: Techniques and mechanisms for displaying an image with structures of a pixel array. In an embodiment, pixels of the pixel array each include three chrominance elements and a fourth luminance element. Of the four elements of a given pixel, a first subset of the elements are aligned along a first line, a second subset of the elements are aligned along a second line offset from the first line, and a third subset of the elements are aligned along a third line extending athwart the first line and the second line, wherein two of the elements are located on opposite sides of the third subset. In another embodiment, image data processing, for displaying an image with the pixel array, includes updating luminance parameters of a plurality of pixel data sets independent of any evaluation to update one or more types of chrominance parameters of the plurality of pixel data sets.

Abstract: A display apparatus and a method of controlling the same are provided. The display apparatus includes an input device configured to receive a display signal including a video signal, a graphic signal, and an alpha value, a calculator configured to calculate effective bits of data of the video signal and the graphic signal, the effective bits of data being used to perform alpha-blending based on an alpha value of each pixel from the display signal, an alpha-blender configured to perform alpha-blending on the display signal by using the effective bits of data calculated by the calculator and the alpha value, and a display configured to display an image generated according to the alpha-blended display signal.

Abstract: An image display method, adapted to an electronic device having a screen, an image capturing unit, and a light sensor, includes the following steps. A preview image captured by the image capturing unit is received and processed so as to generate a plurality of pixel luminance values of the preview image. A light illumination of an ambient light detected by the light sensor is received. An output Gamma lookup table among a plurality of Gamma lookup table is selected according to the pixel luminance values and the light illumination of the ambient light. An adjusted pixel luminance value corresponding to each of the pixel luminance values is generated based on the output Gamma lookup table so as to accordingly display the preview image on the screen with sunlight readability. An electronic device is further provided in the invention to implement the above method.

Abstract: A tileable display panel includes an array of display pixels including central display pixels near a center of the array having a center pixel pitch and perimeter display pixels along a perimeter of the array. A perimeter region surrounds the array. The perimeter region includes a first side that is joinable to a second side of another instance of the tileable display panel to form a multi-panel display. The perimeter region has a width that is greater than at least half the center pixel pitch such that a gap between adjacent perimeter display pixels of the tileable display panel and the other instance of the tileable display panel when forming the multi-panel display is greater than the center pixel pitch. The gap is visually masked by increasing a characteristic of the perimeter display pixels adjacent to the gap relative to the same characteristic of the central display pixels.

Abstract: When an amplifier supplies to a drive line a driving signal based on an input voltage corresponding to a data value indicated by input data, and feeds to an output line a current corresponding to a voltage value on the drive line, the amplifier precharges the drive line at start of increase or decrease of the input voltage. Furthermore, the amplifier stops the precharge when the data value indicated by the input data is smaller than a reference value, or when a difference between a data value at present and a data value immediately therebefore in a series of data values indicated by the input data is smaller than a reference difference value.

Abstract: A batteryless digital information display device includes a display unit including an electronic-paper (e-paper) display module configured to maintain information displayed thereon in absence of power supply, an interface unit configured to receive data from an external device management apparatus and to receive power from the device management apparatus, and a control unit configured, upon being connected to the device management apparatus, to supply the power from the device management apparatus to the e-paper display module via the interface unit and to update information displayed on the e-paper display module based on the data received from the device management apparatus via the interface unit.

Abstract: An organic light emitting diode display panel is disclosed which is defined into a plurality of pixel regions and includes: first through third pixel drivers arranged in each of the pixel regions and configured to each drive respective organic light emitting diode; and first through third pixel electrodes arranged in each of the pixel regions and connected to the first through third pixel drivers. The first and second pixel drivers within an odd-numbered pixel region share a first power supply line with each other. The third pixel driver within the odd-numbered pixel region shares a second power supply line with the first pixel driver within an even-numbered pixel region adjacent to the odd-numbered pixel region. The second and third pixel electrodes are arranged along a first direction parallel to a major axis of the first pixel electrode and disposed to expend along second directions perpendicular to the first direction.

Abstract: A picture signal processing circuit includes a gamma correction section configured to perform gamma correction on a picture signal; and a gamma modification section configured to provide an offset component corresponding to one or both of a refresh rate and a light emission duty, to the picture signal gamma-corrected by the gamma correction section.

Abstract: A scanning structure for driving a pixel circuit of an active-matrix organic light-emitting diode display includes a Sn?1 signal unit having a pixel driving circuit for receiving an upper scan signal with a downward scanning direction and a lower scan signal with an upward scanning direction as an input signal. The pixel driving circuit includes a first input end and a first output end. A driving signal can be received by the first input end, transformed to a first scan signal by the pixel driving circuit, and outputted by the first output end. A Sn signal unit includes a Sn pixel circuit having a second input end coupled to the first output end and a second output end. The first scan signal can be received by the Sn pixel circuit and transformed to a second scan signal, and the second scan signal can be outputted by the second output end.

Abstract: An OLED (organic light-emitting diode) pixel structure comprises a substrate, first and second control components, first, second, and complementary electrode layers, and first and second light-emitting layers. The first and second control components are disposed above the substrate and electrically coupled to, respectively, the first and second electrode layers. There are first and second neighborhoods defined in the pixel structure, and the substrate traverses both of the neighborhoods. The first electrode layer is disposed in the first neighborhood and comprises a reflective layer. The first light-emitting layer is disposed on and electrically coupled to the first electrode layer. The second electrode layer is transparent and disposed in the second neighborhood. The second light-emitting layer is disposed on and electrically coupled to the second electrode layer. The complementary electrode layer is disposed on and electrically coupled to the light-emitting layers.

Abstract: A display device includes a first substrate, a second substrate disposed opposite to the first substrate, a connector connected to a first surface of each of the first and second substrates and covering at least a portion of side surfaces of each of the first and second substrates, a photo sensor disposed on the connector and facing the side surface of the first substrate, and a fixing member disposed between the first substrate and the connector, in which the photo sensor is inserted into the fixing member.

Abstract: According to one embodiment, a display device includes a light source, a dimming panel which comprises a dimming area including sub-areas arrayed in a matrix and controls a transmittance of light from the light source in each of the sub-areas, and a display panel which comprises a display area including pixels arrayed in a matrix and displays an image due to incident light transmitted through the dimming panel thereon.

Abstract: A driving method of an electrophoretic display having at least one display particle is provided. The driving method includes the following steps. A first voltage difference is applied to a data line in a first period, in which the data line corresponds to one of the display particles. At least one particle restore period is inserted in the first period, and a second voltage difference is applied to the data line in the particle restore periods, in which the second voltage difference is different from the first voltage difference. With this method disclosed here, the maxima brightness, maxima darkness, contrast ratio, color saturation, bistability, and image updating time can be largely improved.

Abstract: A luminance control system includes a display with a backlight module, a detecting module, and a control module with a control circuit. The control module is coupled between the backlight module and the detecting module. The detecting module is configured to detect ambient light outside the display and to transmit a detecting signal to the control circuit. A control signal is transmitted from the control circuit to the backlight module according to the detecting signal. The backlight module is configured to automatically adjust illumination according to the control signal to control luminance of the display. The present disclosure further discloses a display luminance control method.

Abstract: According to one embodiment, a display device includes a light source, a light guide including an entrance surface facing the light source, and an exit surface from which light incident on the entrance surface exits, a display panel including a display area in which a plurality of display pixels are arranged, the display area facing the exit surface, the display panel is configured to selectively transmit light incident on the display area for displaying an image in the display area by driving the display pixels, and a dimming panel including a dimming area facing the display area and the exit surface, the dimming panel is configured to change a transmittance of light incident on the dimming area for each portion in the dimming area.

Abstract: A detection system and a method capable of automatically adjusting a gray scale are provided. The detection system includes a detection lens (1), wherein the detection lens (1) is configured to collect a mask alignment image (10) and a substrate alignment image (11) formed by images of a mask alignment mark (8) on a mask (6) and a substrate alignment mark (9) on the glass substrate (7); and an automatic filter device (4) provided in a light path in which the detection lens (1) forms the substrate alignment image (11), wherein the automatic filter device (4) comprises an automatic gray scale detection module (12), a control module (14) and a filter (13). The detection system and method capable of automatically adjusting a gray scale can automatically change the gray scale of the substrate alignment image (11), thereby to improve the automatization degree of the detection system.

Abstract: A method may involve obtaining a desired emitted brightness value for a brightness module or a display module implementable in a display device. The desired emitted brightness value may be between a first configured emitted brightness value and a second configured emitted brightness value of a plurality of configured emitted brightness values outputable by the brightness module. The second configured emitted brightness value may be higher than the first configured emitted brightness value. The method may also involve determining one of the first configured emitted brightness value and the second configured emitted brightness value to be an actual emitted brightness value outputted by the display module or the brightness module. The method may further involve determining a gain for adjusting brightness of an image content outputted by the display module to compensate a difference between the desired emitted brightness value and the actual emitted brightness value.

Abstract: A data driver includes a digital-to-analog converter, a control signal output circuit, and an output buffer. The digital-to-analog converter generates first data voltages and second data voltages based on image data and a polarity control signal. Each first data voltage has a positive polarity, and each second data voltage has a negative polarity. The control signal output circuit outputs a first output control signal and a second output control signal based on the polarity control signal. A phase of the second output control signal is different from a phase of the first output control signal. The output buffer outputs the first data voltages based on the first output control signal and outputs the second data voltages based on the second output control signal.

Abstract: A liquid crystal array substrate includes a number of pixels, each pixel includes a main region, a first sub-region, and a second sub-region. The main region includes a first thin film transistor (TFT), the first sub-region comprises a second TFT, and the second sub-region comprises a third TFT. Gates of the first TFT, the second TFT, and the third TFT of each pixel are connected to a first scan line, a source of the first TFT is connected to a first data line, a drain of the first TFT is connected to one corresponding pixel electrode; sources of the second TFT and the third TFT are connected to a second data line, drains of the second TFT and the third TFT are respectively connected to corresponding pixel electrodes.

Abstract: A display device comprises a display panel. The display panel comprises a plurality of gate lines, a plurality of data lines, a plurality of sub-pixels, a gate driver connected to the gate lines, and a data driver connected to the data lines. The data driver comprises a de-multiplexer controller for outputting a plurality of control signals to a plurality of control lines, a data process portion for outputting a plurality of data signals to a plurality of signal lines, and a first de-multiplexer comprising a plurality of switches connected to the de-multiplexer controller through the control lines, the data process portion through at least one of the signal lines, and the sub-pixels through the data lines. Wherein the switches of the first de-multiplexer keep turned on within a first horizontal period.

Abstract: Provided is a display device, including: a driving circuit including a first output terminal group including at least one gate signal output terminal, and a second output terminal group including at least one source signal output terminal; and a plurality of gate lead-out lines configured to transmit a gate signal to a plurality of gate lines, in which each or the plurality of gate lines is electrically connected to at least one of the gate lead-out lines, and the first output terminal group is arranged between two adjacent second output terminal groups.

Abstract: A display driver IC includes an external pin to receive a select signal and a liquid crystal display device. The display device is selectively operated in a first mode or a second mode based on the level of the select signal for 3-dimensional display. The liquid crystal display device includes a timing controller to generate control signals, a source driver to convert digital data to a pixel voltage, and a panel to display an image.

Abstract: To provide a display device which can perform external correction in parallel with display operation. The display device includes a plurality of pixels arranged in a matrix and a plurality of reading circuits provided outside the pixels. Each of the pixels includes a light-emitting element and a transistor which supplies current to the light-emitting element. In the display device, in a blanking period of the display device, a row in which all the pixels are displayed in black is selected so that a reading signal is input thereto; data on current characteristics of the transistors included in the pixels in the selected row is read out, and at the same time, display is performed in pixels in rows other than the selected row; and a signal for black display is input in the selected row so that the pixels in the row are displayed in black.

Abstract: A shift register unit and a gate drive apparatus are disclosed. The shift register unit comprises a pre-charge module configured to provide a voltage of a first voltage source to a first node under the control of an input signal from the signal input terminal, the first node being an output node of the pre-charge module; a pull-up module, and configured to provide a clock signal from a first clock signal terminal to a signal output terminal under the control of a voltage of the first node; a reset module configured to provide a voltage of a second voltage source to the first node under the control of an input signal from a reset signal terminal; and a pull-down module configured to maintain the first node and the signal output terminal at a low level during non-operating time of the shift register unit.

Abstract: According to one embodiment, a display device includes signal lines, scanning lines, pixel switching elements, a signal line driving circuit, a scanning line driving circuit and a display pixel, wherein the signal line driving circuit is configured to apply a voltage, which is identical to a voltage of the counter-electrode, to all the signal lines when a control signal, which is supplied from an outside of the insulative substrate, is at a first logic level, and the scanning line driving circuit is configured to turn on all the pixel switching elements when the control signal is at the first logic level, and to turn off the pixel switching elements at different timings when the control signal is at a second logic level.

Abstract: According to an aspect, an electronic device includes a first face, a second face, a display unit arranged on the first surface, a notification unit arranged on the second surface, an attitude detecting unit, and a control unit. The attitude detecting unit detects whether attitude of the electronic device is a first attitude, in which the first surface faces upward in the vertical direction, or a second attitude, in which the first surface faces downward in the vertical direction. When the attitude detecting unit detects the second attitude, the control unit prevents displaying on the display unit and enables the notification unit to give a notification.

Abstract: A power supply module includes a source driver power supply circuit, a gate driver power supply circuit, a first capacitor group, a second capacitor group and a switch module. The source driver power supply circuit and the gate driver power supply circuit are utilized for driving a source driver and a gate driver of a display device, respectively. The first capacitor group includes at least one first storage capacitor for storing electric charges for driving source driving signals, and at least one first flying capacitor. The second capacitor group includes at least one second storage capacitor for storing electric charges for driving gate driving signals, and at least one second flying capacitor. The switch module is utilized for switching the first capacitor group to be used for the gate driver power supply circuit or switching the second capacitor group to be used for the source driver power supply circuit.

Abstract: An image processing system and method include first processing a color stimulus relative to a first anchor, and then second processing a processed color stimulus relative to a second anchor. The first processing unit and the second processing unit preserve relative attributes of the color stimulus to enhance color sensation.

Abstract: This disclosure provides systems, methods and apparatus for a laser-pumped phosphor backlight for display devices. In one aspect, a display includes a laser backlight configured to emit light, a plurality of phosphors that emit light at a respective wavelength when stimulated by light emitted by the laser backlight, and a waveguide including a diffraction grating positioned between the laser backlight and the plurality of phosphors. In some implementations, the diffraction grating may be configured to direct the light emitted by the laser backlight at a different intensity for each of the plurality of phosphors. For example, the diffraction grating may direct the light at different intensities for each of the plurality of phosphors by generating a diffraction pattern such that the light emitted by the laser backlight is distributed at different relative intensities for each of the plurality of phosphors.

Abstract: A display driving circuit includes a first bias circuit, a second bias circuit, a selector, and an output buffer. The first bias circuit generates a first bias voltage set. The second bias circuit generates a second bias voltage set. The selector selects one of the first and second bias voltage sets based on a bias selection signal. The output buffer buffers a grayscale voltage corresponding to display data and outputs the buffered grayscale voltage The output buffer is biased based on the first or second bias voltage set selected by the selector.

Abstract: Apparatuses and methods for reproducing an image in a plurality of displays are provided. The method includes obtaining a display identifier that identifies a position of a display among the plurality of displays, based on information on an arrangement of the plurality of displays transmitted by the image reproduction control apparatus; obtaining an image segment to be reproduced in a display corresponding to the display identifier among the plurality of displays, from the image; determining the importance factor of the image segment based on at least one of the image and the viewing environment of the plurality of displays; generating an encoded image segment by encoding the image segment according to an encoding method corresponding to the importance factor; and transmitting a bitstream including the display identifier, the importance factor and the encoded image segment to the image reproduction control apparatus.

Abstract: A non-transitory storage medium stores instructions executable by an information processing device including an operation device and a display. The instructions cause the information processing device to: display a first image; display a cropping frame for cropping of the first image when the operation device accepts a user operation for displaying the cropping frame in a state in which the first image is displayed; rotate the first image about a center of the cropping frame when the operation device accepts a user operation for rotating the first image in a state in which the first image and the cropping frame are displayed; and rotate the first image about a center of the first image when the operation device accepts a user operation for rotating the first image in a state in which the first image is displayed, and the cropping frame is not displayed.

Abstract: A Dynamic Vision Sensor (DVS) where pixel pitch is reduced to increase spatial resolution. The DVS includes shared pixels that employ Time Division Multiplexing (TDM) for higher spatial resolution and better linear separation of pixel data. The pixel array in the DVS may consist of multiple N×N pixel clusters. The N×N pixels in each cluster share the same differentiator and the same comparator using TDM. The pixel pitch is reduced (and, hence, the spatial resolution is improved) by implementing multiple adjacent photodiodes/photoreceptors that share the same differentiator and comparator units using TDM. In the DVS, only one quarter of the whole pixel array may be in use at the same time. A global reset may be done periodically to switch from one quarter of pixels to the other for detection. Because of higher spatial resolution, applications such as gesture recognition or user recognition based on DVS output entail improved performance.

Abstract: An electronic guitar pick, system, system and method may include an enclosure forming a cavity, the enclosure having a first end that is substantially pointed and a second end opposite the first end that is substantially flat, the enclosure having a thickness proximate the cavity greater than a thickness proximate the first end. The electronic guitar pick, system, and method may further include a sensor contained, at least in part, within the cavity and configured to generate a sensor output based on an interaction with the enclosure and a sensory output device, communicatively coupled to the sensor, configured to output a sensory output based, at least in part, on the sensor output.

Abstract: A piccolo comprising a conical-bore headjoint, and a cylindrical-bore main body having toneholes of particular size disposed at particular intervals along the length of the body.

Abstract: A musical instrument has at least a first rototom and a second rototom with their respective drum heads facing an opposite direction from each other. The musical instrument has two rototoms with each rototom having a first hoop supporting a drum head, a spider support with a second hoop, a tension hoop and an annulus. A generally horizontal shaft portion extends between the first hoop and the second hoop, wherein the spider support is movable on the shaft portion to vary a separation distance between the first hoop and the second hoop. A connector member is situated between the annuli of the first and second rototum to support the rototoms with their respective drum heads facing opposite directions.

Abstract: A computer-implemented method includes receiving input data including MIDI events arranged in a timeline, determining a target grid position from among the plurality of grid positions, determining a search range around the target grid position, and identifying a set of MIDI events within the search range around the target grid position. The method further includes determining a reference point for the set of MIDI events based on a function of the set of MIDI events, adjusting a position of the reference point toward the target grid position, determining a proportional movement for each MIDI event on the timeline based on its location relative to the adjusted reference point, and adjusting each MIDI event based on the determined proportional movement. The function of the set of MIDI events can be a weighted average based on one or more MIDI characteristics of the set of MIDI events.

Abstract: As part of a system, a device is provided as part of a system, the device being for capturing vibrations produced by an object such as a musical instrument. The device has a first sensor placed in contact with a surface of the drum, such as a rim of the drum, and a second sensor placed at a fixed location relative to the drum, but not touching the drum. A method may be provided for interpreting the output of the sensors within the system, the method comprising identifying the onset of an audio event in audio data, selecting a window in the data for analysis, applying transforms to generate a representation of the audio event, and comparing that representation to expected representations in a model.

Abstract: A passive amplifier for a stringed instrument (such as an electric guitar) comprises a pickup and a resonator. The pickup is removably attached at one end to the headstock of the stringed instrument and extends substantially normal to the headstock. The resonator is attached to the other end of the pickup. The resonator has a generally flared structure. An aperture in the pickup extends from one end to the other end.

Abstract: Disclosed is an ultrasonic transducer mounting assembly comprising an ultrasonic transducer element, a transducer housing inside which the ultrasonic transducer element is arranged, and an accommodation unit inside which the transducer housing is clamped in a clamping section. The disclosed assembly is characterized in that the clamping section comprises at least one bearing that has at least one rolling element, in particular at least one ball bearing that has at least one ball, for acoustically decoupling the transducer housing from the accommodation unit.

Abstract: Systems, apparatuses and methods for integrating adaptive noise cancellation (ANC) with communication features in an enclosure, such as an incubator, bed, and the like. Utilizing one or more error and reference microphones, a controller for a noise cancellation portion reduces noise within a quiet area of the enclosure. Voice communications are provided to allow external voice signals to be transmitted to the enclosure with minimized interference with noise processing. Vocal communications from within the enclosure may be processed to determine certain characteristics/features of the vocal communications. Using these characteristics, certain emotive and/or physiological states may be identified.

Abstract: A method of active noise cancellation and an associated system for cancelling noise within an enclosed space are described. The method involves detecting acoustic noise outside of the enclosed space. The method then involves generating a noise cancellation signal outside of the enclosed space, such that the acoustic noise is cancelled prior to the acoustic noise entering the enclosed space.

Abstract: A noise controller includes a first control unit that outputs a control signal for outputting sound for reducing noise to a first speaker, a first characteristic circuit that generates a signal by performing convolution, using a transfer characteristic from the second speaker to a second sound collector, on a control signal output from the first control unit to a second speaker, a subtractor that subtracts the signal generated by the first characteristic circuit from an output signal of a second sound collector and outputs a resultant signal. The first control unit generates the control signal to be output to the first speaker while the output signal from the subtractor serves as a reference signal so that an output signal of the first sound collector is minimized, and outputs the control signal to the first speaker.

Abstract: Disclosed are embodiments for use in an articulatory-based text-to-speech conversion system configured to establish an articulatory speech synthesis model of a person's voice based on facial characteristics defining exteriorly visible articulatory speech synthesis model parameters of the person's voice and on a predefined articulatory speech synthesis model selected from among stores of predefined models.