Abstract: Disclosed herein are an apparatus and method for retrieving on-chain data based on an index. The apparatus includes memory in which at least one program is recorded and a processor for executing the program. The program may include a blockchain connection manager for recording data in at least one node or retrieving data from at least one node and outputting the same by being connected to a blockchain network formed of multiple nodes, a blockchain index manager for creating and managing an index for data stored in at least one node, and a query engine for requesting storage of data resulting from a transaction in a corresponding node through the blockchain connection manager, creating an index on the stored data by interworking with the blockchain index manager, and acquiring and outputting data that is retrieved based on the index through the blockchain connection manger in response to a retrieval request.

Abstract: A strain sensor may have a conductive elastic yarn including a first fiber having a predetermined length and a shape of a fiber yarn and a second fiber having electrical conductivity and a sheet shape. The strain sensor may have a pair of wiring members electrically connected to both ends of the conductive elastic yarn. The conductive elastic yarn, with the second fiber wrapped around the first fiber, is twisted in a coil shape.

Abstract: The present disclosure relates to an organic electroluminescent device. The organic electroluminescent device according to the present disclosure includes a deuterated organic electroluminescent material, so it can exhibit a low driving voltage and high luminous efficiency.

Abstract: Disclosed are a method of and an apparatus for 3D visualization of the root canal curvature of a tooth. The method includes (a) displaying a CT image of one or more teeth on the basis of CT image data, (b) three-dimensionally rendering at least a portion of the root canal of a target tooth when a dental practitioner selects the target tooth from the CT image, and (c) visualizing a curvature in a region of the root canal that is three-dimensionally rendered using a visual factor.

Abstract: A device and method for controlling a power supply. The method includes: a voltage signal in a primary winding is delayed, and the delayed voltage signal is sampled and held after a time when a rectifying diode stops conducting a current, then the sampled and held signal is used as a feedback signal of the power supply. Therefore, only one sampling and holding circuit is needed, the area of the circuit can be reduced and the cost of the integrated circuit can be decreased, meanwhile regulation characteristics are not deteriorated.

Abstract: A device and method for controlling a power supply. The method includes: a first correction signal is generated according to a down-slope waveform and a second correction signal is generated according to an up-slope waveform, in a period of the switching element. Therefore, two kinds of corrections can be performed by using an oscillator, while the area of the circuit can be reduced and the cost of the integrated circuit can be decreased.

Abstract: A device and method for controlling a power supply. The method includes: monitoring a feedback signal of a feedback terminal; determining whether the feedback signal of the feedback terminal is not a pulse signal; and terminating an on/off operation of a switching element when the feedback signal of the feedback terminal is not a pulse signal. Therefore, an abnormal status of the device can be correctly detected with a simple structure when the feedback terminal is open or is shorted with other terminals, while an error operation and a damage of the device can be avoided.