Abstract: Provided are a method and apparatus for obtaining a minimum cost vector for making a skyline object in a multi-dimensional space. The method includes calculating respective vector values having a query point and respective moving points to which the query point is moved as both end points in a multi-dimensional space having a plurality of coordinate axes, and selecting a vector value whose moving point is included in a skyline and has the minimum distance value from the query point as the minimum vector value from among the vector values.

Abstract: Disclosed herein are an apparatus and method for enabling clients to participate in data storage in a distributed file system. The client device of a distributed file system according to the present invention includes a storage determination unit and a file reading unit. The storage determination unit determines whether first metadata information, including a global generation number of the chunk corresponding to a file to be read, has already been stored in the local storage. The file reading unit performs a read operation on the file using local data corresponding to the first metadata information if, as a result of the determination, it is determined that the first metadata information has already been stored.

Abstract: Disclosed is a dynamic load balancing system. The dynamic load balancing system includes a resource management master managing bare servers that do not execute services and having a hierarchical structure and a service master dynamically allocating the bare servers to a load balancing server or a service execution server or dynamically releasing the pre-allocated load balancing server or service execution server by the bare servers, in consideration of monitoring information on a state or performance of a server and service requirements to be provided.

Abstract: Provided are a large-scale cluster monitoring system and a method for automatically building/restoring the same, which can automatically build a large-scale monitoring system and can automatically build a monitoring environment when a failure occurs in nodes. The large-scale cluster monitoring system includes a CM server, a BD server, GM nodes, NA nodes, and a DB agent. The CM server manages nodes in a large-scale cluster system. The DB server stores monitoring information that is state information of nodes in groups. The GM nodes respectively collect the monitoring information that is the state information of the nodes in the corresponding groups to store the collected monitoring information in the DB server. The NA nodes access the CM server to obtain GM node information and respectively collect the state information of the nodes in the corresponding groups to transfer the collected state information to the corresponding GM nodes.

Abstract: Provided is an availability prediction method for a high availability. The method includes calculating a basic survival probability that the other node survives until a failure on one node of two nodes constituting a cluster is fixed, and determining an optimal number of nodes meeting a preset reference availability probability by calculating an availability probability for a predetermined range of the number of nodes on the basis of the basic survival probability. The method determines the number of nodes in the high availability cluster so as to match a reference availability probability, and is able to accomplish an optimal configuration of a cluster by calculating the availability probabilities for combinations between active node and passive nodes and between head nodes and switches.

Abstract: Provided are a method and apparatus for obtaining a minimum cost vector for making a skyline object in a multi-dimensional space. The method includes calculating respective vector values having a query point and respective moving points to which the query point is moved as both end points in a multi-dimensional space having a plurality of coordinate axes, and selecting a vector value whose moving point is included in a skyline and has the minimum distance value from the query point as the minimum vector value from among the vector values.

Abstract: Provided is a contents distribution management system and method for supporting a plurality of global servers that provide the contents and managing the contents by applying different policies based on the global server and service type of the contents. The inventive system comprises a plurality of global servers for supplying contents to a plurality of local servers, each global server having a large capacity contents library, and the local servers for managing the contents provided from the global servers based on global servers and service types using contents tables, and providing a contents service in response to a contents streaming service demand from a last terminal using a local contents cache.

Abstract: A method of data placement and control in a block-divided distributed disk array is provided. At first, data to store is divided into logical blocks, and each of the divided logical blocks is further divided into a plurality of data blocks. Then, a parity block is created through performing an XOR operation on the data blocks of each logical block in a unit of a strip, and the parity block is arranged at the first block of a strip unit. Then, parity blocks are arranged at a next block of a previous logical block's the last data block through a left/right shifting for uniformly arranging the parity blocks through out all disks in order to fill an empty block between the logical blocks.

Abstract: A hierarchical system configuration method and an integrated scheduling method for offering a multimedia streaming service on a two-level double cluster system are provided.

Abstract: Provided are a system and a method for distributing multimedia streaming service request based on wide area network which can efficiently support multimedia streaming service in wide area network. The system for distributing multimedia streaming service request based on wide area network includes a user terminal, a wide area server, and a local server. The user terminal requests multimedia streaming service. The wide area server for selecting a local server which is disposed nearest to the user terminal and has node availability and service availability, and providing contents requested by the user terminal to the selected local server. The local server provides the multimedia streaming service to the user terminal using the contents provided from the wide area server.

Abstract: Provided are a cluster system, which makes general nodes appear as if they provide seamless services without failure when seen from the outside, and a method for operating the cluster system. The cluster system for operating individual nodes in a distributed management manner includes a board server having a task board registered with a task list, an agent server for managing the task board, and a plurality of general server nodes for performing a corresponding task on the basis of the task list, among which a failed general server node is replaced with another normal general server node.

Abstract: Provided are a large-scale cluster monitoring system and a method for automatically building/restoring the same, which can automatically build a large-scale monitoring system and can automatically build a monitoring environment when a failure occurs in nodes. The large-scale cluster monitoring system includes a CM server, a BD server, GM nodes, NA nodes, and a DB agent. The CM server manages nodes in a large-scale cluster system. The DB server stores monitoring information that is state information of nodes in groups. The GM nodes respectively collect the monitoring information that is the state information of the nodes in the corresponding groups to store the collected monitoring information in the DB server. The NA nodes access the CM server to obtain GM node information and respectively collect the state information of the nodes in the corresponding groups to transfer the collected state information to the corresponding GM nodes.

Abstract: Provided is an availability prediction method for a high availability. The method includes calculating a basic survival probability that the other node survives until a failure on one node of two nodes constituting a cluster is fixed, and determining an optimal number of nodes meeting a preset reference availability probability by calculating an availability probability for a predetermined range of the number of nodes on the basis of the basic survival probability. The method determines the number of nodes in the high availability cluster so as to match a reference availability probability, and is able to accomplish an optimal configuration of a cluster by calculating the availability probabilities for combinations between active node and passive nodes and between head nodes and switches.

Abstract: A fractional caching method and an adaptive contents transmitting method using the same are provided. The fractional caching method includes the steps of setting up a divided location for dividing a certain object into two parts, receiving an evict request for acquiring a space in the inside of the cache, when the evict request is transmitted, dividing a plurality of objects stored in the cache into a prefix-Object located in the head of the object and a suffix-Object located in the tail of the object from the divided location, and removing only the suffix-Object of each object, wherein the divided location is set up at a size rate that a size of the prefix-Object is in inverse proportion to the number of the destination types.

Abstract: Provided are a method for generating an instantaneous decoding refresh (IDR) unit for trick play, and a trick play system and method using the same. The trick play system includes: a speed information input unit configured to receive a speed value; a transmission condition determining unit configured to determine instantaneous decoding refresh (IDR) transmission conditions based on the speed value inputted through the speed information input unit; a double-speed IDR-unit generating unit configured to generate a double-speed IDR-unit by adjusting the number and data size of video frames to be transmitted in accordance with the transmission conditions determined by the transmission condition determining unit; and a transmitting unit configured to transmit the generated double-speed IDR-unit to an external user terminal.

Abstract: A method of data placement and control in a block-divided distributed disk array is provided. At first, data to store is divided into logical blocks, and each of the divided logical blocks is further divided into a plurality of data blocks. Then, a parity block is created through performing an XOR operation on the data blocks of each logical block in a unit of a strip, and the parity block is arranged at the first block of a strip unit. Then, parity blocks are arranged at a next block of a previous logical block's the last data block through a left/right shifting for uniformly arranging the parity blocks through out all disks in order to fill an empty block between the logical blocks.

Abstract: A method and apparatus for providing a peer-to-peer (P2P) based streaming service are provided. The method provides a streaming service in a peer-to-peer (P2P) network comprising a plurality of peers. That is, a receiving peer requests a plurality of transmitting peers having contents for a streaming service among peers in the P2P network to transmit the contents. Then, the receiving peer receives identical portions of the same content from the plurality of transmitting peers at the same time. After receiving, the receiving peer provides a streaming service for the received content from a first transmitting peer among the plurality of transmitting peers to a user.

Abstract: A fractional caching method and an adaptive contents transmitting method using the same are provided. The fractional caching method includes the steps of setting up a divided location for dividing a certain object into two parts, receiving an evict request for acquiring a space in the inside of the cache, when the evict request is transmitted, dividing a plurality of objects stored in the cache into a prefix-Object located in the head of the object and a suffix-Object located in the tail of the object from the divided location, and removing only the suffix-Object of each object, wherein the divided location is set up at a size rate that a size of the prefix-Object is in inverse proportion to the number of the destination types.

Abstract: A file level striping method adds an option for indicating whether or not to support file level striping to a file creation interface in a file system, extends an inode structure to include a last disk ID field, initializes the last disk ID when the file is created in the file system, allocates a physical block based on the last disk ID when the physical block allocation is requested at the time of file I/O request in the file system, and modifies the last disk ID value to reflect the physical block allocation made by a volume manager. An apparatus using the file level striping method includes a number of disks for storing information actually, the volume manager for logically grouping a number of disks and a file system for creating files on said logical volume and performing I/O operations.

Abstract: Provided is a contents distribution management system and method for supporting a plurality of global servers that provide the contents and managing the contents by applying different policies based on the global server and service type of the contents. The inventive system comprises a plurality of global servers for supplying contents to a plurality of local servers, each global server having a large capacity contents library, and the local servers for managing the contents provided from the global servers based on global servers and service types using contents tables, and providing a contents service in response to a contents streaming service demand from a last terminal using a local contents cache.