Abstract: The present invention discloses a method of distributing files over a network, which can attain a proper balance of transfer rates of active spanning trees used between a transmitting node and a receiving node and minimize the time taken for transferring a large file in a P2P (Peer-to-Peer) environment by forming an optimal set of distribution trees with reference to the link costs between the transmitting node and the receiving node and distributing chunk files through the optimal set of distribution trees. The method comprises the steps of: forming a set of spanning trees between a transmitting node and a receiving node and forming a minimum cost tree group by the sum of the link costs of links constituting each of the spanning trees; adjusting the transfer rate of each spanning tree belonging to the minimum cost tree group in accordance with the link cost of each spanning tree belonging to the minimum cost tree group; and transferring chunk files through the spanning trees whose transfer rate is adjusted.

Abstract: A hydraulic circuit having a holding valve of an external pilot pressure operation type is provided, which can make a double check valve, which is installed to prevent an actuator from being pushed due to leakage of hydraulic fluid of a main control valve, be opened by an external signal pressure being supplied to shift the main control valve.

Abstract: Provided is a method and system for streaming multimedia data between hetero UPnP networks configured of a private network. The method comprises establishing a communication channel with a relay peer; establishing a virtual communication channel with a specific extensible home connector selected from a plurality of extensible home connectors connected with the relay peer; searching multimedia data to play from multimedia data in the specific extensible home connector which exists on the UPnP network through the virtual communication channel; establishing a communication environment through the UPnP internet gateway of the specific extensible home connector in case of demanding play of the searched multimedia data; and receiving multimedia data from the specific extensible home connector through the communication environment.

Abstract: An apparatus and method for automatically migrating user's working data by using automatic work data migration apparatuses connected respectively to work devices. In the method, the automatic work data migration apparatus detects that the user leaves or accesses the work device. User work data related to the work device are collected and the collected user work data stored in the automatic work data migration apparatus, if it is detected that the user leaves the work device. The storage location information of the user work data is provided to another automatic work data migration apparatuses connected to the automatic work data migration apparatus. The automatic work data migration apparatus searches the storage location information of the user work data if it is detected that the user accesses the work device. The automatic work data migration apparatus connected to the work device accessed by the user receives the user work data related to a work executed in the previous work device.

Abstract: An apparatus and method for managing application context is provided. A first one of a plurality of terminals, each including at least one application, collects and transmits context information of the application to a migration server so that it is stored and managed in the migration server. The migration server transmits the stored and managed context information to a second terminal corresponding to the first terminal in response to a request of the second terminal. The second terminal restores context based on the context information received from the migration server. This can reproduce the same application and desktop environments as those previously set to be suitable for each work situation, thereby increasing user convenience.

Abstract: A method and system for collecting and restoring application state is provided. To process application state information, the system registers various types of applications, searches for an application control library of an application which a user has selected from registered applications, dynamically links to the found application control library, and selectively collects and restores state information of the application using the dynamically linked application control library. Thus, the system can dynamically add or modify an application control interface for selectively collecting and restoring the application state information, thereby improving the security of personal data.

Abstract: Disclosed is a system for dynamically updating remote service objects to manage a network device having various characteristics by Java RMI (Remote Method Invocation), and a method thereof. The system includes a network device manager for authenticating a transmission message communicated between a network device and a management device and transferring and initializing objects for management of the network device, and a management agent. The management method includes a remote object transmission step, a remote object authentication step, a remote object installation step, and a network device management step.