Abstract: A method for locating a failure of a communication line according to self-adjusted priorities of the test points in the order of high failure probability in a communication line management system, includes the steps of organizing the test points, information on the test history of the test points, and test point search priorities (TSPs) representing the priorities of the test points in the order of high failure probability into a test database, searching the test database to determine the testing order of the test points according to the TSPs, testing the test points in the testing order to locate the failure, and revising the values of the data fields of the TSPs according to the test results and the location of the failure.

Abstract: A method for providing a connection between a client and heterogeneous database management systems, includes the steps of: a) generating a thread in response to a request message transmitted from the client; b) determining what is the request message and operating a database driver to process the request message by referring to a client information management table; and c) registering identification information of a client and a database in the client information management table and transmitting an execution result corresponding to the request message from the database driver to the client.

Abstract: A method for requesting a grant for Medium Access Control (MAC) being applied to a Passive Optical Network (PON) system. The method includes the steps of: a) deciding a period of a mini slot (Tms), which is necessary for a plurality of Optical Network Units (ONU) to transmit upstream cells to an Optical Line Termination (OLT); b) deciding a period of a divided slot (Tds) and a link overhead (Co) based on the period of the mini slot (Tms); c) calculating a length of the mini slot based on information to be transmitted to the OLT and a protocol being used; and d) requesting a grant for a MAC protocol between the plurality of the ONUs by calculating and allocating optimal parameters based on the length of the mini slot.

Abstract: Disclosed is a roaming service system in a CDMA service area for GSM service subscribers, which comprises a CDMA system comprising a CDMA HLR storing information on subscribers' locations and services, a CDMA MSC connected to the CDMA HLR and accessing calls, and a CDMA terminal wirelessly connected to the CDMA MSC and capable of having a SIM card removably installed therein; a GSM system comprising a GSM HLR storing information on the subscribers' locations and services, a GSM MSC connected to the GSM HLR and accessing calls, an authentication center (AuC) connected to a GSM network and authenticating terminals, and a GSM terminal wirelessly connected to the GSM MSC; and an IRGS connected between the CDMA system and the GSM system and converting signals to execute signal communications between the systems, and when a subscriber of a service provided by the GSM system moves to an area in which the subscriber can use the service provided by the CDMA system and installs the subscriber's SIM card

Abstract: An optical device having a current blocking layer of a buried ridge structure and a fabrication method thereof are disclosed. This invention reduces a leakage current between active layer and ion implant layer in buried ridge structure. To minimize leakage current, a P-N-P current blocking layer and an ion implanting current blocking layer are combined. An optical device of the present invention includes: active layers of a mesa structure in a predetermined region on a substrate; a first current blocking layer of a P-N-P structure, which is placed to cover the mesa structure; and a second current blocking layer of a buried ridge structure, which is placed to surround the environs of the first current blocking layer.

Abstract: The invention relates to a dispersion flattened fiber (DFF) with high negative dispersion and a manufacturing method thereof. The dispersion flattened fiber comprises a central core; ring-type cores and low refractive regions alternately formed outside the central core; a cladding surrounding outside the ring-type cores and low refractive regions; and a coating outside the cladding. Since the dispersion flattened fiber has the dispersion of −20 to −60, it has a wide range of application and can be used for various purposes in the field of optical telecommunication.

Abstract: The present invention relates to an optical filter whose a sidelobe disturbing a characteristic of an optical filter by weighting an optical coupling efficiency between waveguides is controlled upon applying a selective area growth method in a wavelength selective variable semiconductor optical filter and method of fabricating the same. The present invention can control the thickness of growth layer selectively by controlling the width of the dielectric thin film mask whose the growth is not achieved in the selective area growth method, can control the distance between two waveguides of the wavelength selective variable semiconductor optical filter by applying the result on the distance control between two waveguides. Accordingly, there can be changed an optical coupling efficiency between two waveguides spatially.

Abstract: The present invention relates to a method for fabricating an optical device integrated with a spot size converter to reduce defect and low reflectivity in a butt-joint portion, the method including the steps of: a) depositing a first clad layer, an active layer and a second clad layer sequentially on the (100) plane of a semiconductor substrate; b) forming on the second clad layer a double dielectric mask of which the lower layer has a relatively wider width than that of the upper layer, exposing one side of the second clad layer; c) wet-etching the first clad layer, the active layer and the second clad layer in a buried ridge structure by using the double dielectric mask, and exposing the (111)A plane of the active layer tilted towards the (100) plane by a predetermined angle; d) growing a spot size conversion region on the (111)A plane of the active layer; and e) removing the double dielectric mask.

Abstract: A modular jack includes a housing, a first signal pair, and a second signal pair. The first signal pair passes through the housing and includes a first conductor and a second conductor. A first imaginary plane contains the first and the second conductor. The second signal pair passes through the housing and includes a third conductor and a fourth conductor. A second imaginary plane contains the third and the fourth conductor, which are bent at least one time to cross each other inside the housing. The first and the second imaginary plane form a first angle of 80 to 90 degrees inside the housing before the crossing of the third and the fourth conductor while they form a second angle of 0 to 10 degrees inside the housing after the crossing thereof.

Abstract: A method is presented for finding a shortest path from a starting place to a destination place in a traffic network including one or more turn restrictions, one or more U-turns and one or more P-turns using a Dijkstra algorithm. The method as sets a virtual arc between nodes, and assigns a virtual arc value. A smallest travel time value is selected out of total travel time values for all nodes except for the starting node, by considering existing arcs between nodes and the virtual arc and assigning the smallest travel time value to a permanent label node. The shortest path is determined by tracing the permanent nodes starting from the destination node.

Abstract: A method for manufacturing a fiber package for use in an optical communication device, is comprised the steps of: preparing a ribbon-type fiber stack having a pair of sheared sides, the ribbon-type fiber stack being provided with a plurality of fragmental optical fibers, each of fragmental optical fibers including a core surrounded by a cladding; partially peeling the claddings from the fragmental optical fibers to expose the cores; forming gratings into the exposed cores; and installing a pair of side connections on the pair of sheared sides in the ribbon-type fiber stack, thereby forming a fiber package. In the invention method, the ribbon-type fiber stack and a pair of side connections are utilized, which can remove a need for the step of packing the optical fiber(s), simplifying the formation of the fiber stack.

Abstract: A method for producing a visual rhythm in a video system, includes the steps of: a) sampling a portion of pixels contained at each of frames; and b) producing the visual rhythm summarizing changes of video contents by using the result of the sampling.

Abstract: The present invention relates to a method for mid-span branching of optical fiber cable which makes the mid-span branching possible without excess length of the optical fiber cable by forming main branching part and sub branching part for branched cores to be taken out from an existing main cable. It is an object of the present invention to provide a method for mid-span branching that provides marginal length of the existing main cable from which the branch cable branches off without the excess length of cables.

Abstract: An apparatus and a method for video transmission in a video conferencing system in which in order to efficiently transmit the speaker's picture in meetings, conferences, workshops and the like, the text data is separately transmitted by being separated from the speaker's picture.

Abstract: An apparatus and a method for detecting channel information from wavelength division multiplexed (WDM) optical signals by using a wavelength selective photo detector. This apparatus and method can monitor channel status in a simple, rapid and economical way.

Abstract: A system for converting a heterogeneous compressed moving picture data, includes: a variable length decoder for generating variable length decoded data as first compressed moving picture data from a first data bit stream; a compressed moving picture data analyzer for analyzing layer types of the first compressed moving picture data; a layer-matching device for matching layers of the first compressed moving picture data to layers of second compressed moving picture data, thereby generating the second compressed moving picture data; and a variable length encoder for generating variable length coded data as a second data bit stream. Thereby, the system can convert an H.261 compressed moving picture data to an MPEG-1 compressed moving picture data on a compression domain.

Abstract: The present invention relates to a method for multi-step filtering a candidate object which is filtered by a minimum bounding rectangle (MBR); and, more particulary, to a method of multi-step filtering a candidate object by employing a minimum maximum point (MMP) filter to improve spatial query filtering process performance by refiltering the candidate objects, which are filtered by using a rotated minimum bounding rectangle (Rotated Minimum Bounding Rectangle) surrounding spatial objects during filtering process at a step of spatial query filtering and refining of spatial database, by using spatial filter, i.e., MMP filter.

Abstract: Disclosed is a Brillouin erbium-fiber laser system producing multiwavelengths with a dual spacing of 10 GHz and 20 GHz. The Brillouin erbium-fiber laser system includes: a Sagnac reflector generating even- and odd-order Strokes waves by launching input lights, a first unit forming a first resonator with the Sagnac reflector, wherein the first unit is coupled to a first directional coupler in the Sagnac reflector, a second unit forming a second resonator with the Sagnac reflector, wherein the second unit is coupled to the first directional coupler in the Sagnac reflector, and a third unit for inputting Brillouin pump light into one of first and the second units, whereby the optical fiber laser system outputs multiwavelengths with a dual spacing.

Abstract: An asynchronous transfer mode (ATM) host adapting apparatus comprising: a storage block for storing packet information, received cells, and parameters; an ATM network interface handling block for performing direct memory access of ATM cells and parameter stored therein, segmenting transmit packet information, reassembling received cells, transmitting and receiving the ATM cells to physical media cell received, and arbitrating in the direct memory access; and a secondary interface block for connecting the storage block to the ATM network interface handling block.

Abstract: The present invention relates to an apparatus of a high speed optical buffer utilizing a cell pointer so that optical cells of asynchronous transfer mode can be stored and processed at high speed without the restriction of processing time for a high speed network architecture, wherein an internal switch of the apparatus would be controlled by extracting optically the cell pointer indicating starting point by using a high speed optical buffer with terahertz optical asymmetric demultiplex (Terahetz Optical Asymmetric Demultiplexer) in order to avoid a collision of each cell which is transmitted on a same channel especially at the high speed network.