Abstract: Provided herein is a distributed file system including a meta data server configured to store and manage meta data of a file; and a data server configured to store and manage data and attribute information of the file, wherein, in response to a writing request from a client, the meta data server stores data requested to be changed in a delta chunk of a read-only snapshot file, and connects the original file and the read-only snapshot file in an inode structure.

Abstract: Provided herein is a filing system creating and deleting apparatus, comprising an available inode pool in which inodes are to be stored, a file system object creating processor creating an inode allocating request signal in response to a file system creating request from an external resource, an inode allocating processor allocating at least one of inodes stored in the available inode pool in response to the inode allocating request signal, a file system object deleting processor creating an inode deallocating request signal in response to a file system deleting request from the external resource, an inode deleting thread collecting inodes requested to be deleted corresponding to the file system deleting request, and an inode deallocating processor deallocating the inode requested to be deleted from the inode deleting thread, wherein a number of inodes stored in the available inode pool is limited to no more than a maximum inode number in the available inode pool, and the inode requested to be deleted creates

Abstract: The present disclosure relates to: a method for preparing an animal in which the human immune system is expressed, by using human-induced pluripotent stem cells; and an animal prepared by the method.

Abstract: A virtual machine host server includes a virtual machine in which a guest operating system is installed and operated, a cache manager for processing at least one of an open request, a close request, and an input/output request for a disk image file of the virtual machine, which is stored in a storage system, and managing a boot workload map and a boot segment, a cache device for caching the boot segment, and a prefetch manager for prefetching the boot segment from the cache device.

Abstract: A method for diagnosing rheumatoid arthritis, based on the detection of citrullinated autoantigens in a test sample is disclosed. The method diagnoses rheumatoid arthritis more accurately and rapidly. Also disclosed is a kit for carrying out the method.

Abstract: Disclosed are a method and apparatus for reading data in a distributed file system in which a client and a server are separated. In the method and apparatus, a prefetching operation is performed to provide a continuous read function with high performance even in the distributed file system so that an optimum continuous read function of a local file system within the client may be effectively supported when an application program of the client requests continuous reading on a file (or chunk).

Abstract: Disclosed are an apparatus and a method for distribution processing of data, and a storage server and the apparatus for distribution processing of data includes: a metadata management unit providing metadata information corresponding to data to a metadata server to verify information of an original storage server and one or more copy storage servers to store the data from the metadata server; and a data management unit creating a message including the information on the storage servers verified by the metadata management unit and the data, and transmitting the message to a storage server having a higher priority according to priorities of the storage servers to store the corresponding data.

Abstract: The present invention aims to diagnose rheumatoid arthritis more accurately and rapidly, and relates to a method and a kit for diagnosing rheumatoid arthritis, based on the detection of citrullinated autoantigens in a test sample.

Abstract: Disclosed is a method of calculating parity. The method dividing, by a client system, a file which is to be stored into chunks of a preset size and distributively storing the chunks in a plurality of data servers; sending, by the client system, a data write complete notification message to a metadata server; storing, by the metadata server, a file sent through the data write complete notification message in a recovery queue; and sending, by the metadata server, a random data server a parity calculation request for the file stored in the recovery queue.

Abstract: A method of efficiently replicating data stored in data servers in an asymmetric file system is provided. A replication processing apparatus of a network transmits a replication request only to a data server that does not replicate data so that it is possible to reduce replication time of a data block and to extend time-out with reference to a response message transmitted by the data server. In addition, each of the data servers may efficiently transmit copy data to another data server by a pipeline data transmission method.

Abstract: In order to synchronize a file between transmitting and receiving nodes, when a file is changed, a hint provider of the transmitting node provides a change file and change information about the change file as a hint to a change log generator, the change log generator generates a change log with reference to the change file and the hint, and the generated change log is transmitted to the receiving node by a change log transmitter.

Abstract: A method and system that can completely delete garbage data in a distributed network system are provided. Because it is impossible to initially access a data server, data to delete is not deleted, and thus when a garbage file is generated, a generated garbage file can be completely deleted. In this case, by performing a deletion operation of a garbage file in a distributed data server unit, operation efficiency can be maximized.

Abstract: There are provided a system and method for providing a virtual desktop service using a cache server. A system for providing a virtual desktop service according to the invention includes a host server configured to provide a virtual desktop service to a client terminal using a virtual machine, a distributed file system configured to store data for the virtual machine, and a cache server that is provided for each host server group having at least one host server, and performs a read process or a write process of data using physically separate caches when the read process or write process of the data is requested from the virtual machine in the host server.

Abstract: A metadata server of a distributed file system calculates an access frequency of a file and changes a maintaining method of chunks of a data server for dividing data of the file into chunk units to store the chunks in a stripe in accordance with access frequency of the file.

Abstract: A replicated file deduplication apparatus generates a hash key of a requested data block, determines whether the same data block as the requested data block exists in data blocks of a replicated image file that is derived from the same golden image file as the requested data block using the hash key of the requested data block, and records, if the same data block as the requested data block exists, information of a chunk in which the same data block as the requested data block is stored at a layout of the requested data block.

Abstract: An apparatus for managing files in a hybrid storage system establishes a file management policy based on a directory unit using files stored in first and second storage devices and manages the files of the first storage device and the second storage device in accordance with the established file management policy based on the directory unit.

Abstract: The present disclosure relates to a unit-wall structure for a liquefied gas storage tank on land, which enables rapid and easy construction of a cylindrical wall of the storage tank by stacking a plurality of pre-produced unit-wall structures to overlap one another. The unit-wall structure includes iron rods arranged lengthwise and breadthwise therein, wherein the unit-wall structure has an arc shape so that a plurality of unit-wall structures are stacked to form a cylindrical wall of the storage tank.

Abstract: The present disclosure relates to a method of constructing a liquefied gas storage tank on land, which enables rapid and easy construction of walls of a cylindrical storage tank by stacking a plurality of pre-produced unit-wall structures to be stacked or superposed with respect to one another. The method includes: producing unit-wall structures made of concrete and each having iron rods arranged lengthwise and breadthwise therein, stacking the unit-wall structures in a cylindrical arrangement, and connecting the unit-wall structures adjacent and in longitudinal and lateral directions with respect to each other to form a wall of the storage tank.

Abstract: Disclosed are an apparatus, a system, and a method for recovering meta data using fragmentary information. The system for recovering meta data includes: a data server storing recovery information for recovering at least one data file and meta data related to each of the data file; and a meta data server storing the meta data related to the data files and receiving the recovery information from the data server when the meta data are lost to recover the lost meta data. By this configuration, the exemplary embodiment of the present invention stably can the lost meta data of the meta data server by using the recovery the meta data and prevent the phenomenon that the meta data collides with each other on the same directory hierarchical structure.

Abstract: The present invention relates to an apparatus and method of performing an error recovery process in an asymmetric clustering file system that has higher efficiency in data recovery when a data server in an asymmetric clustering file system fails than a method of processing the data recovery in the metadata server. The present invention includes receiving a chunk list requiring recovery by a data server included in the other data server groups than a data server group including a failed data server among a plurality of data server groups, requesting chunk data necessary for recovering an erroneous chunk from a data server in the other data server groups to the other data servers than the failed data server in the data server group, and recovering the erroneous chunk based on the chunk data by the data server in the other data server group.