Abstract: An optical imaging system includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens sequentially arranged in numerical order from an object side of the optical imaging system toward an imaging plane of the optical imaging system and each having a refractive power, wherein an entire field of view of the optical imaging system is 50° or greater, and TTL/f<1.0, where TTL is a distance from an object-side surface of the first lens to the imaging plane, and f is an overall focal length of the optical imaging system.

Abstract: An optical imaging system includes a first lens having a convex image-side surface, a second lens having a concave object-side surface, a third lens, a fourth lens, and a fifth lens disposed sequentially from an object side. The optical imaging system satisfies 4.8<f/IMG_HT<9.0, where f is a focal length of the optical imaging system, and IMG_HT is half a diagonal length of an imaging surface of an image sensor.

Abstract: An inverter driving apparatus includes an inverter having a plurality of legs respectively corresponding to each of a plurality of phases and the control unit generating space vector modulation signals based on a phase voltage command, each of the space vector modulation signals corresponding to each of the plurality of phases, respectively, determining whether an output voltage of the inverter corresponding to at least one space vector modulation signal of the space vector modulation is in a non-linear region by determining whether each voltage of the space vector modulation signals is included in a predetermined range, generating a terminal voltage command by determining whether or not to apply an offset voltage to each of the space vector modulation signals based on the determination of the non-linear region, and controlling a turn-on state of at least one switch included in each of the plurality of legs by modulating the terminal voltage command based on pulse width modulation.

Abstract: A method and apparatus for downloading a Secure Micro (SM) bootloader of a receiver in a Downloadable Conditional Access System (DCAS) is provided. The method includes generating, by a transmitter, an SM bootloader for the receiver and adding the generated SM bootloader to firmware to be transferred to the receiver, sending, by the transmitter, the firmware to the receiver, and performing, by the receiver, registration by receiving the firmware, locating an SM bootloader in the firmware, and registering the located SM bootloader. In the DCAS, a receiver may download or install an SM bootloader through an online or offline procedure.

Abstract: In order to identify an optical cable for optical communication from a remote place, a Sagnac interferometer including two strands of an optical fiber is formed in the optical cable, and a worker in the remote place applies a disturbance of a popping sound to an optical cable to be identified. The disturbance applied by the worker is detected and regenerated in the form of a sound. The optical cable can be easily identified by comparing the regenerated signal and the disturbed signal in the remote place to thereby prevent an incorrect optical cable from being cut. In addition, the optical cable can be more precisely identified by selecting a different light detecting frequency component in accordance with environment conditions.

Abstract: Provided are an apparatus and a method for injecting liquid crystal into a hollow optic fiber. The apparatus includes: a first holder and a second holder each of which has a fluid passage for holding corresponding one end of the hollow optic fiber to be communicated with the fluid passage a container connected to a tube disposed with a valve at the fluid passage of the second holder and storing liquid crystal; an air supplying device connected to the first holder and the container through tubes having a plurality of valves to select an air passage for making the hollow optic fiber vacuous by sucking air out of the hollow optic fiber and forcedly injecting liquid crystal into the hollow optic fiber by supplying an air pressure.

Abstract: An apparatus for controlling gas layer thickness on the surface of casting rolls in a twin roll strip caster includes: a pair of chambers fixedly mounted on both lateral portions of the meniscus shield in a width direction of a strip; blocking units for blocking introduction of pollutants into the molten metal pool, wherein each of the blocking units includes front and rear barrier members which are mounted on each of the chambers and in close contact with an outer periphery of each casting roll and a blower for injecting inert gas toward the outer periphery of each casting roll; operating units for adjusting the thickness and the width of gas layers at both ends of the casting rolls, wherein each of the operating units includes suction lines connected with each chamber to transmit a suction force to ends of each casting roll and a pair of movable plates slidably assembled to both side portions within each chamber for being reciprocated by movable members; and a control unit for controlling the suction force

Abstract: Provided are an apparatus and a method for injecting liquid crystal into a hollow optic fiber. The apparatus includes: a first holder and a second holder each of which has a fluid passage for holding corresponding one end of the hollow optic fiber to be communicated with the fluid passage a container connected to a tube disposed with a valve at the fluid passage of the second holder and storing liquid crystal; an air supplying device connected to the first holder and the container through tubes having a plurality of valves to select an air passage for making the hollow optic fiber vacuous by sucking air out of the hollow optic fiber and forcedly injecting liquid crystal into the hollow optic fiber by supplying an air pressure.

Abstract: In order to identify an optical cable for optical communication from a remote place, a Sagnac interferometer including two strands of an optical fiber is formed in the optical cable, and a worker in the remote place applies a disturbance of a popping sound to an optical cable to be identified. The disturbance applied by the worker is detected and regenerated in the form of a sound. The optical cable can be easily identified by comparing the regenerated signal and the disturbed signal in the remote place to thereby prevent an incorrect optical cable from being cut. In addition, the optical cable can be more precisely identified by selecting a different light detecting frequency component in accordance with environment conditions.

Abstract: An apparatus for controlling gas layer thickness on the surface of casting rolls in a twin roll strip caster includes: a pair of chambers fixedly mounted on both lateral portions of the meniscus shield in a width direction of a strip; blocking units for blocking introduction of pollutants into the molten metal pool, wherein each of the blocking units includes front and rear barrier members which are mounted on each of the chambers and in close contact with an outer periphery of each casting roll and a blower for injecting inert gas toward the outer periphery of each casting roll; operating units for adjusting the thickness and the width of gas layers at both ends of the casting rolls, wherein each of the operating units includes suction lines connected with each chamber to transmit a suction force to ends of each casting roll and a pair of movable plates slidably assembled to both side portions within each chamber for being reciprocated by movable members; and a control unit for controlling the suction force