Abstract: Provided sets a limit of execution threads which can be simultaneously processes in an input/output system and compares the number of threads which are being currently executed with the limit of execution threads at the time of requesting an input/output event from a thread and manages a job of processing the input/output event in accordance with the comparison result. The apparatus for asynchronous input/output processing of a multi-thread according to the present invention restricts the number of threads which are processed in the asynchronous input/output system as many as the limit of execution threads to prevent deterioration of performance caused due to context switching overhead of the thread and efficiently manage the thread.

Abstract: A data transfer apparatus, system and method using the same are provided. A data transfer system according to an exemplary embodiment includes a user process space, a kernel space and a hardware space. A plurality of user processes are executed in the user process space. The kernel space includes a kernel thread. The hardware space performs an input/output according to the input/output request of the each user process. When input data based on the input request are received to the hardware space, the data transfer system checks whether the user process requesting the input is in an execution state, and allows the kernel thread to copy the input data from the kernel space to the user process space when the user process is in the execution state.

Abstract: Provided is an integrated semiconductor light source using locking characteristic by an external light injection, including: an active region controlling an optical gain and an optical output by current injection; and a passive region having a structure integrated with the active region and moving a cavity mode by current injection or voltage application to lock injection light.

Abstract: Provided are a network scheduler and a network scheduling method capable of effectively managing network bandwidths by selectively supporting a work conserving mode to network entities by using an improved token bucket scheme. The network scheduler selectively supports a work conserving mode to network scheduling units (NSUs) serving as network entities by using a token bucket scheme, such that the network scheduler ensures an allocated network bandwidth or enables the NSUs to use a remaining bandwidth. The network scheduler manages the NSUs by classifying the NSUs into a green state, a red state, a yellow state, and a black state according to a token value, a selection/non-selection of the work conserving mode, and an existence/non-existence of the packet request to be processed.

Abstract: Provided are an apparatus and a method for communication interface between application programs on virtual machines using a shared memory. The apparatus, includes: a request dividing unit for checking a type of socket request information transmitted from a first socket application program on a first virtual machine through a socket interface and dividing the socket request information based on the checked information; a Transmission Control Protocol (TCP) socket connecting unit setting up TCP socket connection with a second socket application program on a second virtual machine based on the divided socket request information for control request; and a shared memory connecting unit for setting up shared memory connection through the set up TCP socket connection and transmitting/receiving data with the second socket application program through the set up shared memory connection based on the divided socket request information for data transmission/reception.

Abstract: A secure policy description method and apparatus for a secure operation system are provided. In the secure policy description method, a secure policy template is defined to have a subject, an object, and a permission assigned to the subject corresponding to the object. Then, the defined secure policy template is transformed to a TE (Type Enforcement) secure policy to be applied to a SELinux (Security enhanced Linux).

Abstract: A network block device using a network asynchronous I/O method is provided. The network block device includes an asynchronous I/O interface for managing a plurality of socket connections; an request process unit for analyzing a request from a client through a socket, reading data from a disk and transmitting the read data to the client through the socket, and writing the data transmitted through the socket to the disk, through the asynchronous I/O interface; and a request processing unit for collecting a result event of processing an operation asynchronously requested by the request processing unit and informing the request processing unit of the collected result event, through the asynchronous I/O interface.

Abstract: Provided is a method for providing personalized information lifecycle management service based on a personal data management policies. The method includes the steps of a) determining whether there is material change between a system for providing the information lifecycle management service and a first storage device connected to the system through a network; b) identifying the personal data management policies for the connected first storage device; c) identifying user's context information; d) performing data management based on the identified personal data management policies and context information; and e) updating the metadata with the execution result of data management.

Abstract: Provided is an optical deflector for deflecting radiation beams. The optical deflector includes: a peripheral region having a first effective refractive index; and a deflection pattern region having a predetermined shape and a second effective refractive index, wherein the second effective refractive index differs from the first effective refractive index. Here, due to the deflection pattern region having the predetermined shape, the radiation beams are deflected in a direction starting from a certain point. By using the optical deflector, the locus of a light source can be designed in one of various forms, such as a straight line, a circle, an ellipse, or a parabola.

Abstract: Provided is a tunable external cavity laser diode using a variable optical deflector wherein the variable optical deflector, in which a refractive index varies according to an electrical signal, is arranged in a triangular shape between a concave diffraction grating and a reflective mirror. Since a resonant frequency is changed using the electrical signal rather than the mechanical movement, the stable operation and continuous high-speed tenability may be enabled. In addition, when the tunable external cavity laser diode according to the present invention is implemented in an InP/InGaAsP/InP slab waveguide, a variable time determined by the carrier lifetime may be reduced to several nanoseconds or less, the miniaturization is enabled, and the manufacturing costs are significantly reduced due to the process simplification.

Abstract: An optical modulator using a dynamic single mode laser diode (DSM-LD) integrated with a deflector is disclosed. The optical modulator for coupling a light beam to an optical fiber, the optical modulator includes: a laser diode for generating the light beam; and a deflector for deflecting a direction of the light beam according to an electric signal externally applied and outputting the defected light beam to the optical fiber, wherein the laser diode and the deflector are integrated with a multi-layer semiconductor structure in such a way that the light beam is modulated by changing a defection angle of the deflector.

Abstract: Provided are a tunable demultiplexer and a tunable laser, having an optical deflector in which a refractive index of a core layer of a deflection pattern region having a predetermined shape varies in response to an external electrical signal so that the optical deflector deflects incident light in the radial direction.

Abstract: Provided is a wavelength tunable light source that can electrically tune wavelengths by monolithically integrating an optical amplifier, a beam steering unit, and a concave diffraction grating on a single substrate. A beam is deflected by the beam steering unit when an electrical signal is applied to two electrodes installed in the beam steering unit to be incident on the diffraction grating, and then diffracted by the diffraction grating according to the incidence angle such that part of the beam with a specific wavelength is reflected, thereby achieving wavelength tuning. Since the wavelength tuning is achieved electrically, the wavelength tunable light source is structurally stable and has a rapid wavelength tuning rate.

Abstract: Provided are a tunable demultiplexer and a tunable laser, having an optical deflector in which a refractive index of a core layer of a deflection pattern region having a predetermined shape varies in response to an external electrical signal so that the optical deflector deflects incident light in the radial direction.

Abstract: Disclosed is a high speed optical signal processor which includes a saturable absorber area including a substrate, an active layer, a clad layer and a first upper electrode which are sequentially formed on one face of the substrate, and a first lower electrode formed on the other face of the substrate; and a gain-clamped optical amplifier area including a substrate having a diffraction grating for generating a laser beam, an active layer, a clad layer and a second upper electrode which are sequentially formed on one face of the substrate, and a second lower electrode formed on the other face of the substrate, the second upper electrode being isolated from the first upper electrode of the saturable absorber area.

Abstract: An optical modulator using a dynamic single mode laser diode (DSM-LD) integrated with a deflector is disclosed. The optical modulator for coupling a light beam to an optical fiber, the optical modulator includes: a laser diode for generating the light beam; and a deflector for deflecting a direction of the light beam according to an electric signal externally applied and outputting the defected light beam to the optical fiber, wherein the laser diode and the deflector are integrated with a multi-layer semiconductor structure in such a way that the light beam is modulated by changing a defection angle of the deflector.

Abstract: Filter-free wavelength converters for separating and rejecting an optical input signal. A first input port couples a continuous wave (CW) light. A second input port couples an optical input signal. A multimode interference semiconductor optical amplifier (MMI-SOA) determines the output port with the input port and intensity-modulation of the CW light with the optical input signal. A first output port guides the converted signal, and a second output port guides the optical input signal.

Abstract: The present invention relates to all-optical OR and XOR logic elements employing saturable absorbers as optical gates. Saturable absorbers are arranged in paths of the Mach-Zehnder interferometer, respectively. If the total power of an input optical signal and a continuous wave signal is higher than a transparent input power of the saturable absorbers, the input optical signal passes through the saturable absorbers, and then the optical signals through the two paths are combined, so that it is possible to obtain the operational characteristics of the OR and XOR logic elements. According to the present invention, unlike the optical logic element using a cross-phase modulation by a semiconductor optical amplifier, phase difference depending upon the input optical power is not generated between two paths, so that it is possible to alleviate a restriction of an allowable range of the input optical power.

Abstract: The present invention relates to an optical deflector driven by an electrical signal, and a wavelength tunable external resonator using the same. The optical deflector of a triangle shape, capable of controlling the refractive index of a beam depending on the electrical signal, is positioned between a reflection mirror and a diffraction grating in a Littman-Metcalf mode external resonator or between a lens and the diffraction grating in a Littrow mode external resonator. Thus, even with the reflection mirror and the diffracting grating fixed, the refractive index of the beam generated from a laser diode can be controlled by adjusting the electrical signal applied to the optical deflector, so that beam having a specific wavelength can be focused and the wavelength can be rapidly and consecutively tuned.

Abstract: Disclosed is a tunable wavelength semiconductor laser diode which comprises a FP(fabry-parrot) laser diode array for producing at least two light beams, a combiner for combining the light beams output by an end of the laser diode array, a lens for collimating the light beams output by another end thereof, a grating for diffracting the light beams collimated by the lens, and a reflector for reflecting the light beams diffracted by the grating to feed the reflected light beams back to the laser diode array.