• Journal of the Korean Geotechnical Society
• /
• v.35 no.8
• /
• pp.5-15
• /
• 2019

This study was conducted to propose a reasonable requirement regulation of cutoff barriers composed of bottom layer and vertical barrier of offshore landfill for the prevention of contaminant leakage. The bottom layer was composed of impermeable clay layer; vertical walls were composed of double walls; outer wall was composed of steel sheet pile which registed against outer force; cutoff vertical barrier took the role of inner wall. Seepage-advection-dispersion numerical analysis was conducted using SEEP/W and CTRAN/W programs under steady and unsteady flows. The results showed that the values calculated under steady flow showed higher migration of pollutant than those of unsteady flow. The values calculated under steady flow are more valid from a design point of view. Under steady flow and the bottom clay layer and when the vertical barrier are homogeneous and completely well installed, respectively, the minimum required cutoff regulations for hydraulic conductivity, thickness, and embedded depth of the bottom clay layer and vertical barrier were suggested.

• Journal of the Korea Institute of Information Security & Cryptology
• /
• v.31 no.3
• /
• pp.443-452
• /
• 2021

One of the key technologies in edge computing is that it always provides services close to the user by moving data between edge servers according to the user's movements. As such, the movement of data between edge servers is frequent. As IoT technology advances and usage areas expand, the data generated also increases, requiring technology to accurately track and process each data to properly manage the data present in the edge computing environment. Currently, cloud systems do not have data disposal technology based on tracking technology for data movement and distribution in their environment, so users cannot see where it is now, whether it is properly removed or not left in the cloud system if users request it to be deleted. In this paper, we propose a tracking data server to create and manage the movement and distribution of data for each edge server and data stored in the central cloud in an edge computing environment.

• Journal of Platform Technology
• /
• v.8 no.3
• /
• pp.3-9
• /
• 2020

As the need for sharing for research purposes in the medical field increases, the use of a Common Data Model (CDM) is increasing. However, when sharing CDM data, there are some problems in that access control and personal information in the data are not protected. In this paper, in order to solve this problem, access to CDM data is controlled by using an encryption method in a blockchain network, and information of CDM data is recorded to enable tracking. In addition, IPFS was used to share a large amount of CDM data, and Celery was used to automate the sharing process. In other words, we propose a multi-channel automation system in which the information required for CDM data sharing is shared by a trust-based technology, a distributed file system, and a message queue for automation. This aims to solve the problem of access control and personal information protection in the data that occur in the process of sharing CDM data.

• Journal of Korea Society of Industrial Information Systems
• /
• v.14 no.2
• /
• pp.8-15
• /
• 2009

The need for ASP(Application Service Provider) has evolved from the increasing costs of specialized software that have far exceeded the price rage of small to medium sized businesses. There are a lot of technologies that make ASP possible, and software streaming service is one of them Software streaming is a method for overlapping transmission and execution of stream-enabled software. The stream-enabled software is able to run on a device even while the transmission/streaming of the software may still be in progress. Thus, a user does not have to wait for the completion of the software's download prior to starting to execute the software. In this paper, we suggest the new concept of software streaming system implement using the PageFault Interrupt Routine Hooking. As it is able to efficiently manage application, we do not have to install the entire software. In addition, we can save hardware resources by using it because we load basic binaries without occupying the storage space of the hardware.

• Journal of KIISE:Computer Systems and Theory
• /
• v.35 no.1
• /
• pp.1-17
• /
• 2008

Recently, the object based storage devices systems(OSDs) have been actively researched. They are different from existing block based storage systems(BSDs) in terms of the storage unit. The storage unit of the OSDs is an object that includes the access methods, the attributes of data, the security information, and so on. The object has no size limit and no influence on the internal storage structures. Therefore, the OSDs improve the I/O throughput and the scalability. But the backup systems for the OSDs still use the existing backup techniques for the BSDs. As a result, they need much backup time and do not utilize the characteristics of the OSDs. In this paper, we design and implement a new object based backup system that utilizes the features of the OSDs. Our backup system significantly improves the backup time over existing backup systems because the raw objects are directly transferred to the backup devices in our system. It also restores the backup data much faster than the existing systems when system failures occur. In addition, it supports various types of backup and restore requests.

• The Journal of the Korea Contents Association
• /
• v.10 no.12
• /
• pp.70-76
• /
• 2010

This paper Extended ELZW(EBCDIC Lempel Ziv Welch) algorithm uses 2 byte prefix field for pointer of a table and 1 byte suffix field for repeat counter. where, a prefix field uses a pointer(index) of compression table and a suffix field uses a counter of overlapping or recursion text data in compression table. To increase compression ratio, after construction of compression table, table data are properly packed as different bit string in accordance with a alphabet, Hangeul, and pointer respectively. Therefore, proposed ELZW algorithm is superior to 1byte LZW algorithm as 5.22 percent and superior to 2byte LZW algorithm as 8.96 percent.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.8 no.6
• /
• pp.1443-1448
• /
• 2007

In this paper, we implement a distributed computing environment-based travel information service that can use web(internet) and speech interface at the same time and can apply location information, using voice and web browser-based VoiceXML and GPS, to escape the limitations of traditional web(internet)-based travel information services. Because of IVR(Interactive Voice Response) of traditional call center has operated to a pre-installation scenario, it takes much a service time and has the inconveniences that must repeat speech recording according to the revised scenarios in case change response contents. However, suggested VoiceXML and GPS-based travel information service system has advantages that reorganization of system setups is easy, because it consists of the method to update server after make individual conversation scenarios by file format(document), and can provide usefully various travel information in environmental restriction conditions such as the back regions environment, according as our prototype find user's present location using GPS information and then provide various travel information service by this information.

• Journal of KIISE:Computing Practices and Letters
• /
• v.6 no.6
• /
• pp.580-587
• /
• 2000

In this paper, we present a design method of a digital filter converting humming voice melody into MIDI data and a method of adapting it to a distributed multimedia I/O server. MuX uses device-independent DLMs(Dynamic Linking Module) for the inteliace with various I/O devices, and has wave-form audio DLM and MIDI DLM for audio interfaces. In order to expand the audio device interfacing ability of MuX system, we have designed and implemented a filter transforming human voice into MIDI messages. As the methods to input MIDI data are expanded to human voice in addition to MIDI files and MIDI instrument, someone who is not good at playing instruments can also generate the MIDI data, which enables our media interfaces to be used in various applications.

• KIPS Transactions on Computer and Communication Systems
• /
• v.11 no.11
• /
• pp.403-410
• /
• 2022

Non-Fungible Tokens (NFTs) created on the basis of blockchain have their own unique value, so they cannot be forged or exchanged with other tokens or coins. Using these characteristics, NFTs can be issued to digital assets such as images, videos, artworks, game characters, and items to claim ownership of digital assets among many users and objects in cyberspace, as well as proving the original. However, interest in NFTs exploded from the beginning of 2020, causing a lot of load on the blockchain network, and as a result, users are experiencing problems such as delays in computational processing or very large fees in the mining process. Additionally, all actions of users are stored in the blockchain, and digital assets are stored in a blockchain-based distributed file storage system, which may unnecessarily expose the personal information of users who do not want to identify themselves on the Internet. In this paper, we propose an NFT platform using cloud computing, access gate, conversion table, and cloud ID to improve usability and privacy problems that occur in existing system. For performance comparison between local and cloud systems, we measured the gas used for smart contract deployment and NFT-issued transaction. As a result, even though the cloud system used the same experimental environment and parameters, it saved about 3.75% of gas for smart contract deployment and about 4.6% for NFT-generated transaction, confirming that the cloud system can handle computations more efficiently than the local system.

• The KIPS Transactions:PartA
• /
• v.13A no.7 s.104
• /
• pp.615-622
• /
• 2006

Caching in a Wireless Internet Proxy Server Cluster Environment has an effect that minimizes the time on the request and response of Internet traffic and Web user As a way to increase the hit ratio of cache, we can use a hash function to make the same request URLs to be assigned to the same cache server. The disadvantage of the hashing scheme is that client requests cannot be well-distributed to all cache servers so that the performance of the whole system can depend on only a few busy servers. In this paper, we propose an improved load balancing scheme using hashing and Round Robin scheme that distributes client requests evenly to cache servers. In the existing hashing scheme, if a hashing value for a request URL is calculated, the server number is statically fixed at compile time while in the proposed scheme it is dynamically fixed at run time using round robin method. We implemented the proposed scheme in a Wireless Internet Proxy Server Cluster Environment and performed experiments using 16 PCs. Experimental results show the even distribution of client requests and the 52% to 112% performance improvement compared to the existing hashing method.