Abstract: A method and apparatus for packet aggregation in a power line communication network (PLC) are provided. The method of aggregating packets includes: by performing a PLC channel estimation, determining whether or not a channel condition is good; if the channel condition is good, determining whether or not the data desired to be transmitted is suitable for packet aggregation according to the type of data; and if the channel condition is good and the data desired to be transmitted is suitable for the packet aggregation, aggregating packets of the data desired to be transmitted. Since a decision on whether or not to aggregate packets is determined according to a channel condition at a physical level and the type of data at an application level, packet aggregation can be performed in appropriate response to the frequently changing condition of a channel and the characteristic of the data desired to be transmitted.

Abstract: Provided is an apparatus and method of displaying power line communication (PLC) channel information. The apparatus for displaying PLC channel information includes a channel information determining unit which performs channel estimation of a PLC channel, and, based on the channel estimation, determines channel information on the PLC channel including a bandwidth of the PLC channel which is available for a user in a PLC network; and a channel information displaying unit which displays the channel information to the user.

Abstract: A method of data communication between power line communication (PLC) stations belonging to different PLC cells includes transmitting a station ID of a PLC reception station to a PLC cell bridge (CB) of a first PLC cell to which a PLC transmission station belongs, receiving a group identification (GID) and an encryption key of a second PLC cell to which the PLC reception station belongs from the PLC CB of the first PLC cell, encrypting data to be transmitted using the encryption key of the second PLC cell, and transmitting the station ID of the PLC reception station, the GID of the second PLC cell, and the encrypted data, to the PLC CB of the first PLC cell, and an apparatus to perform the method.

Abstract: An optical fiber sensor may include an optical fiber configured to receive a light having a first frequency from a light source and to transmit the light through the optical fiber, the transmitted light having the first frequency and a second frequency which is generated by stimulated Brillouin scattering (SBS), a photodetector configured to receive the transmitted light from the optical fiber and to convert the transmitted light into an electric signal and a sensing circuit configured to calculate an average squared value of the electric signal received from the photodetector, which is dependent on a frequency difference between the first frequency and the second frequency.

Abstract: A digital-to-analog converter (DAC) includes multiple electro-optical converters to generate multiple first optical signals in response to multiple input signals, multiple optical attenuators to attenuate intensities of the first optical signals and to generate multiple second optical signals, an optical coupler to combine the second optical signals and to generate a third optical signal, and a photodetector to convert the third optical signal into an electrical analog signal.

Abstract: A digital-to-analog converter (DAC) includes multiple electro-optical converters to generate multiple first optical signals in response to multiple input signals, multiple optical attenuators to attenuate intensities of the first optical signals and to generate multiple second optical signals, an optical coupler to combine the second optical signals and to generate a third optical signal, and a photodetector to convert the third optical signal into an electrical analog signal.

Abstract: A controlled-release composition and controlled-release microspheres containing an exendin as an active ingredient, and a method of preparing the same are provided. More specifically, a controlled-release composition containing an exendin as an active ingredient, a biodegradable polymer with a specific viscosity, and coating materials, having high bioavailability and showing sustained release of the active ingredient in an effective concentration for a certain period without an excessive initial burst of the active ingredient; controlled-release microspheres containing a core including an exendin as an active ingredient and a biodegradable polymer, and a coating layer coating the core; and a method of preparing controlled-release microspheres including the steps of mixing an exendin, a biodegradable polymer, and a solvent, removing the solvent from the mixture to prepare hardened microspheres, and coating the hardened microspheres to form a coating layer on the surface of each microsphere, are provided.

Abstract: Disclosed herein are novel microbes Thraustochytrium sp. KJS-1 and Bacillus polyfermenticus KJS-2. Also provided is an aquaculture feed additive for use in fisheries, which comprises freeze dried Thraustochytrium sp. KJS-1, freeze dried Bacillus polyfermenticus KJS- 2, and freeze dried Bacillus licheniformis. In addition to providing DHA, an essential nutrient for fish, the aquaculture feed additive shows antibacterial and antifungal activity, thereby preventing fish from dying from bacterial and fungal diseases.

Abstract: A live content switching method, a source device, and a sink device are provided. The method includes switching from first content to second content by using a dummy connection, the second content using the same resource of the source device as the first content. Accordingly, by using dummy connections set between a source device and a sink device, it is possible to switch the sink device from one live content to another live content without the need to cut off existing connections set between the source device and the sink device.

Abstract: Disclosed is a process of preparing sustained release microspheres, containing a biodegradable polymer as a carrier and a drug, using spray drying. The process comprises preparing a solution, suspension or emulsion containing a biodegradable polymer, a drug and a solvent; spray drying the solution, suspension or emulsion; and suspending spray-dried microspheres in an aqueous solution containing polyvinyl alcohol to remove the residual solvent and increase the hydrophilicity of the microsphere surface. The process enables the preparation of microspheres having high drug encapsulation efficiency, almost not having a toxicity problem due to the residual solvent, and having good syringeability. The microspheres prepared according to the present invention release an effective concentration of a drug in a sustained manner for a predetermined period when administered to the body, and are thus useful in the treatment of diseases.

Abstract: A method and apparatus for packet aggregation in a power line communication network (PLC) are provided. The method of aggregating packets includes: by performing a PLC channel estimation, determining whether or not a channel condition is good; if the channel condition is good, determining whether or not the data desired to be transmitted is suitable for packet aggregation according to the type of data; and if the channel condition is good and the data desired to be transmitted is suitable for the packet aggregation, aggregating packets of the data desired to be transmitted. Since a decision on whether or not to aggregate packets is determined according to a channel condition at a physical level and the type of data at an application level, packet aggregation can be performed in appropriate response to the frequently changing condition of a channel and the characteristic of the data desired to be transmitted.

Abstract: Provided are a channel time allocation method and apparatus adopting the same. The channel time allocation method includes: (a) receiving a request of registering in a network from a device; (b) determining whether the network supplying a service required by the device exists; and (c) if the network supplying the requested service exists, performing a procedure of registering in the network, and if the network supplying the requested service does not exist, generating a new network. Since existing MAC protocols can be used in the channel time allocation method, an optimum service is provided in a network environment in which different kinds of services coexist.

Abstract: A method of negotiating channel sharing between adjacent cells when there are a plurality of cells in a power line communication (PLC) network. The method includes attempting to negotiate the channel sharing during a minimum contention access period (CAP) which starts after a maximum beacon period ends and ends before a CAP of each PLC cell ends, wherein the maximum beacon period indicates a maximum size that a beacon frame in a super-frame transmitted from a coordinator of each PLC cell can have. When an attempt to negotiate the channel sharing is made using this method, interference does not occur during channel sharing negotiation, and effective channel sharing can be achieved, thereby eliminating interference between adjacent cells.

Abstract: A power line communication (PLC) network and method, in which a coordinator can be changed. The PLC network includes a coordinator and a standby coordinator. The coordinator performs scheduling coordination in a PLC cell and periodically transmits scheduling information about the scheduling coordination to stations in the PLC cell. The standby coordinator serves as the new coordinator instead of the coordinator when the coordinator does not operate for a predetermined amount of time.

Abstract: A method of distributing group identifiers IDs (GIDs) in a power line communication (PLC) network, a method of receiving the GIDs, an authentication apparatus, and a PLC apparatus are provided. The authentication apparatus includes: an authentication mode storing unit which stores an authentication mode having a value including one of an authentication authorized mode and an authentication unauthorized mode; a GID request receiver which receives a GID request message from a PLC apparatus; and a GID transmitter which, if the authentication mode is the authentication authorized mode, transmits a GID corresponding to the PLC apparatus to the PLC apparatus. Authentication is realized in a PLC media access control layer distributing the GIDs between a PLC apparatus and an authentication apparatus, so manually inputting a GID into the PLC apparatus is not necessary. Further, the GIDs are distributed via the authentication apparatus, thereby centrally managing the GIDs.

Abstract: A method of joining a cell by using a proxy coordinator. The method of joining a cell by using a proxy coordinator includes requesting a second device to operate as a proxy coordinator from a first device positioned out of a beacon frame reachable area of the cell, transmitting a time period to operate as the proxy coordinator allocated by a coordinator of the cell, informing the first device that the second device can operate as the proxy coordinator, transmitting a cell join request to the proxy coordinator from the first device through the second device, and transmitting a beacon frame including time allocation information from the coordinator to the first device through the second device.

Abstract: An apparatus and method of streaming content by adaptively selecting a peer-to-peer (P2P) method or a server-client method according to a network environment, and a computer readable medium having recorded thereon a program for executing the method are provided. The apparatus includes middleware which supports the P2P method, middleware which supports the server-client method, an adaptation manager which provides a list of content, determines one of at least one node and at least one server sharing content which is selected as a source device according to a content sharing method and their available bandwidths, and determines a content sharing method used by the source device as a streaming method, and an application unit which controls the selected content to be received from the source device by using middleware and a transfer layer corresponding to the determined streaming method, and the received content to be reproduced.

Abstract: A method of transmitting data more effectively, and more particularly, a method of classifying service traffic, transmitting data according to the classifications of the service traffic, and performing a contention free slot (CFS) allocation in order to transmit data in a power line communication (PLC) network, and an apparatus to do the same. The data transmission method includes determining transmission priority of data according to service traffic characteristics, and transmitting data according to the determined transmission priority, thereby providing differentiated quality of service (QoS) according to service traffic characteristics.

Abstract: A method of transmitting data more effectively, and more particularly, a method of transmitting data to a group comprising a plurality of reception stations that receive the same data from a transmission station when the stations communicate the data in a power line communication (PLC) network, and an apparatus to do the same. According to the method, a transmission station transmits data to a group including a plurality of reception stations that receive the same data at a time, to prevent a channel bandwidth from being wasted, and to prevent a station that does not desire to receive the data from receiving the data.

Abstract: A method of data communication between power line communication (PLC) stations belonging to different PLC cells includes transmitting a station ID of a PLC reception station to a PLC cell bridge (CB) of a first PLC cell to which a PLC transmission station belongs, receiving a group identification (GID) and an encryption key of a second PLC cell to which the PLC reception station belongs from the PLC CB of the first PLC cell, encrypting data to be transmitted using the encryption key of the second PLC cell, and transmitting the station ID of the PLC reception station, the GID of the second PLC cell, and the encrypted data, to the PLC CB of the first PLC cell, and an apparatus to perform the method.