• The Journal of the Korea Contents Association
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• v.18 no.4
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• pp.178-185
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• 2018

Recently, demands for computer systems with multicore CPUs and high-performance flash-based storage devices (i.e., flash SSD) have rapidly grown in cloud computing, surer-computing, and enterprise storage/database systems. Journaling file systems running on high-performance systems do not exploit the full I/O bandwidth of high-performance SSDs. In this article, we evaluate and analyze the performance of the Linux EXT4 file system with high-performance SSDs and multicore CPUs. The system used in this study has 72 cores and Intel NVMe SSD, and the flash SSD has performance up to 2800/1900 MB/s for sequential read/write operations. Our experimental results show that checkpointing in the EXT4 file system is a major overhead. Furthermore, we optimize the checkpointing procedure and our optimized EXT4 file system shows up to 92% better performance than the original EXT4 file system.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2015.10a
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• pp.224-227
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• 2015

Data transmission via the car driver's tethered smart phone may have a volume-dependent billing in case car driver' phone transmits data in real-time to the remote data center. The on-board diagnosis data generated are temporary stored locally to mobile remote diagnosis application on the car driver's phone, and then transmit to the data center later when car driver connects to the Internet. To increase the easiest of using the remote vehicle application without blocking other tasks to be executing on the cloud, node.js stands as a suitable candidate for handling tasks of data storage on the cloud via mobile network. We demonstrate the effectiveness of the proposed architecture by simulating a preliminary case study of an android application responsible of real time analysis by using a vehicle-to- smart phones applications interface approach that considers the smart phones to act as a remote user which passes driver inputs and delivers output from external applications. In this paper, we propose a study on development of Remote Vehicle fault diagnostic system features web server architecture based event loop approach using node.js platform, and wireless communication to handle vehicle diagnostics data to a data center.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.27 no.3
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• pp.521-530
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• 2017

In this paper, we propose a protection solution against intelligent Ransomware attacks by encrypting not only source files but also backup files of external storage. The system is designed to automatically back up to the cloud server at the time of file creation to perform monitoring and blocking in case a specific process affects the original file. When client creates or saves a file, both process identifiers, parent process identifiers, and executable file hash values are compared and protected by the whitelist. The file format that is changed by another process is monitored and blocked to prevent from suspicious behavior. By applying the system proposed in this paper, it is possible to protect against damage caused by the modification or deletion of files by Ransomware.

• The Journal of Korean Institute of Next Generation Computing
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• v.14 no.5
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• pp.60-70
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• 2018

A software defined storage (SDS) is being deployed in cloud environment to allow multiple users to virtualize physical servers, but a solution for optimizing space efficiency with limited physical resources is needed. In the conventional data deduplication system, it is difficult to deduplicate redundant data uploaded to distributed storages. In this paper, we propose a distributed deduplication method using similarity-based clustering and multi-layer bloom filter. Rabin hash is applied to determine the degree of similarity between virtual machine servers and cluster similar virtual machines. Therefore, it improves the performance compared to deduplication efficiency for individual storage nodes. In addition, a multi-layer bloom filter incorporated into the deduplication process to shorten processing time by reducing the number of the false positives. Experimental results show that the proposed method improves the deduplication ratio by 9% compared to deduplication method using IP address based clusters without any difference in processing time.

• Journal of the Korean Society of Marine Environment & Safety
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• v.28 no.4
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• pp.515-524
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• 2022

To effectively collect, manage, and share the maritime traffic information, it is necessary to identify the technology trends concerning this particular information and analyze its current status and problems. Therefore, this study observes the domestic and foreign technology trends involving maritime traffic information while analyzing and summarizing the current status and problems in collecting, managing, and sharing it. According to the data analysis, the problems in the collecting stage are difficulties in collecting visual information from long-distance radars, CCTVs, and cameras in areas outside the LTE network coverage. Notably, this explains the challenges in detecting smuggling ships entering the territorial waters through the exclusive economic zone (EEZ) in the early stage. The problems in the management stage include difficult reductions and expansions of maritime traffic information caused by the lack of flexibility in storage spaces mostly constructed by the maritime transportation system. Additionally, it is challenging to deal with system failure with system redundancy and backup as a countermeasure. Furthermore, the problems in the sharing stage show that it is difficult to share information with external operating organizations since the internal network is mainly used to share maritime transportation information. If at all through the government cloud via platforms such as LRIT and SASS, it often fails to effectively provide various S/W applications that help use maritime big data. Therefore, it is suggested that collecting equipment such as unmanned aerial vehicles and satellites should be constructed to expand collecting areas in the collecting stage. In the management and sharing stages, the introduction and construction of private clouds are suggested, considering the operational administration and information disclosure of each maritime transportation system. Through these efforts, an enhancement of the expertise and security of clouds is expected.

• Proceedings of the Korean Information Science Society Conference
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• 2011.06c
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• pp.53-55
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• 2011

웹의 미래라고 주목받아 온 클라우드 컴퓨팅은 IT 트랜드의 하나로 IT 기업뿐만 아니라 일반기업까지 많은 관심을 받고 있다. 클라우드 컴퓨팅 서비스의 한 분야인 클라우드 스토리지 서비스는 가장 큰 관심을 받고 있는 분야 중 하나이다. 클라우드 스토리지 서비스는 파일을 스토리지 공간에 저장한 뒤 인터넷이 연결되는 컴퓨터 혹은 모바일기기를 사용하여 원하는 자신의 파일에 접근해 내용을 읽거나 그 자리에서 편집할 수 있는 기능을 가진다. 현재 시중에 제공되는 클라우드 스토리지 서비스는 5GB~20GB 정도의 한정된 저장 공간을 무료로 제공하지만, 추가적인 서비스를 받기 위해서는 비용을 지급해야 한다. 이런 한정된 저장 공간과 서비스 비용을 극복하고자 개인 PC를 활용하여 무한정에 가까운 저장 공간을 확보할 수 있고 무료로 사용할 수 있는 개인용클라우드 스토리지 시스템을 제안한다.

• Annual Conference of KIPS
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• 2014.04a
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• pp.479-482
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• 2014

최근 모바일 컴퓨팅 환경이 발전함에 따라 모바일 디바이스 이용자들에게 다양한 서비스를 제공하기 위한 방법으로 클라우드 스토리지 서비스가 주목받고 있으며, 여러 장치의 데이터 동기화를 지원해준다. 이러한 편리성을 제공하고 있지만, 개인과 기업의 핵심 자료 유출에 따른 보안 이슈가 중요한 문제로 대두되고 있기 때문에, 클라우드 스토리지 보안 검증의 중요성도 증대되었다. 이처럼 클라우드 스토리지 서비스는 보안 검증 과정을 거친다. 본 논문에서는 기존의 클라우드 스토리지 보안 평가 가이드라인의 문제점을 분석하여 다형성, 종속성, 병렬성, 중복성 등을 고려해 효율적인 클라우드 스토리지 보안 평가를 위한 새로운 방법론을 제시 하였다. 제시한 방법론을 이용해 클라우드 스토리지 보안검증 프로세스를 설계하였다.

• Annual Conference of KIPS
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• 2012.04a
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• pp.185-187
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• 2012

최근 클라우드 컴퓨팅 기술은 기존의 서버, 데스크톱 컴퓨팅 환경을 빠르게 변화시키며, 차세대 인터넷 서비스의 핵심 분야로 부각되고 있다. 클라우드 컴퓨팅 기술 중 특히 저비용, 안정성, 확장성, 무결성 그리고 보안성을 가지고 있는 클라우드 스토리지 서비스가 각광 받고 있다. 이에 본 논문은 클라우드 스토리지 기반 기술인 분산 파일 시스템에 관해서 살펴보고, 오픈소스 기반의 분산 파일 시스템인 MooseFS, XtreemFS, GlusterFS, Ceph 등을 이용하여 시스템 구축 및 성능 측정을 수행 하였다. 수행결과 Postmark에서는 GlusterFS, MD5SUM에서는 XtreemFS가 가장 좋은 성능을 보여주었다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.7 no.5
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• pp.1014-1035
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• 2013

With recent advances in wireless communication and low-power miniaturized biomedical sensor and semiconductor technologies, wireless body area networks (WBAN) has become an integral part of the disaster aid system. Wearable vital sign sensors can track patients' status and location, thus enhancing disaster rescue efficiency. In the past few years, most of the literatures in the area of disaster aid system based on WBAN have focused on issues concerning wireless sensor design, sensor miniaturization, energy efficiency and communication protocols. In this paper, we will give an overview of disaster aid, discuss about the types of network communication as well as outline related issues. We will emphasize on analyzing six key issues in employing the disaster aid system. Finally, we will also highlight some of the challenges that still need to be addressed in the future in order to help the disaster aid system be truly and widely accepted by the public.

• Journal of KIISE:Computing Practices and Letters
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• v.16 no.1
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• pp.125-129
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• 2010

Stateless computing supports a mobility of computing environment easily. It is becoming a major technology for securing personal user's information on shared computing environment. With the advance of virtualization technology and cloud computing, stateless computing is an essential part of personal computing environment connectivity (user's setting and data is stored in remote server or some storage, and it can be restored at any computing environment) In this paper, we propose uPC player that supports stateless computing execution environment on Windows. uPC player provides Windows operating system to user by using an uPC OS virtualization module. In this paper, we leverage how uPC player is designed and implemented for supporting a stateless computing execution environment. uPC player provides a desktop switch between host-system execution environment and uPC virtual execution environment. And it needs just one second for loading uPC virtual execution environment by using OS virtualization-based technique.