• Journal of the Korea Institute of Information Security & Cryptology
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• v.30 no.3
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• pp.397-403
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• 2020

With the convenience of real-time conversation, multimedia file and contact sharing services, most people use instant messenger, and its usage time is increasing. Because the messengers contain a lot of user behavior information data, in the digital forensic investigation, they can be very useful evidence to identify user behavior. However, some of useful data can be difficult to acquire or recognize because they are encrypted or deleted. Thus, in order to use the messenger data as evidence, the study of message decryption process and message recovery is essential. In this paper, we analyze the database encryption process of the instant messenger, MalangMalang Talkafe, and propose the method to decrypt it. In addition, we propose the methods to identify the deleted messages and recover from the volatile memory area.

• Monthly Korean Chicken
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• v.4 no.9 s.39
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• pp.2-6
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• 1998

닭고기 위생관리를 위한 HACCP의 의무화 - 농림부, 수해축산농가 재해복구비용 지원 - 육계의 수익을 감소시키는 10가지 - 미국, 육계생산비 8백80원대 - 일본, 고품질의 계육생산과 수입증가 - EU, 수출관련 위생실태 조사단 조사 끝내 - 독일, 육계업 빠르게 성장 - 축협 닭고기 처리 가공장 과잉중복설비 우려

• Review of KIISC
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• v.26 no.4
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• pp.11-15
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• 2016

사이버 위협이 고도화, 지능화함에 따라 사이버 보안사고를 사전에 예방하는 것에는 한계가 있으며, 이제는 보안사고발생을 기정 사실화 하고 이로부터 얼마나 신속하게 사고를 탐지하고, 복구할 수 있는 역량을 구축하는 것이 필요하다. 이러한 현실적 필요성으로 인해 2010년경부터 레질리언스(resilience) 개념을 정보보안에도 접목시키려는 노력이 있었으며, 2016년 4월 템파에서 개최된 SC 27 회의에서도 사이버 레질리언스에 대한 국제표준화 작업이 많은 관심 속에서 논의되었다. 본 논문에서는 사이버 레질리언스에 대한 개념을 정리하고, 사이버 레질리언스 주요 모델과 구현 과제를 기술한다. 마지막으로 사이버 레질리언스 국제표준화 작업에서의 주요 이슈와 활동을 소개한다.

• Magazine of the Korean Society of Hazard Mitigation
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• v.3 no.3 s.10
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• pp.82-89
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• 2003

대만 국가과학위원회에서는 1998년에 지진재해 구조물 피해 사회경제적 손실을 위한 연구를 위해 HAZ-Taiwan 연구 project를 착수하였다. 관련 software인 TELES(Taiwan Earthquake Loss Estimation System)는 3가지 목표를 위해 다양한 입력 및 분석 module로 구성되어 있다. 1. 피해 지진후 재해 평가 2. 재해복구계획 및 가상 시나리오 제공 3. 재해보험을 포함한 재해대응방안 제시 본 논문은 초기재해평가에 이용될 분석 modules개발 및 적용에 초점을 맞추고 있으며, 분석 module은 지반운동강도 액상화 건물피해 및 사상자 평가분석을 포함하고 있다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.4B
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• pp.403-410
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• 2004

In general communication system is composed of processor subsystems, I/O processor subsystems and data storage device subsystems those are classified as their functions. In order to improve the data reliability, all subsystems are redundant. Storage device keeps the operational information such as system related information and charging information, and such informations must be stored in non-volatile memory. Flash memory and battery backup memory are commonly used as the non-volatile storage devices. But such kind of memories are expensive per unit capacity and data can't be restored when lost while not being backed up. In this paper we develop a redundant storage device to store a lot of data safely and reliably in communication system. The device consists of micro-controller, FPGA and hard disk It provides many functions those are rebuilding, automatic remapping, host service and remote host service. Also it is designed to provide host service while rebuilding is being done in order not to interrupt the communication services. The developed device can be used instead of expensive storage device like flash memory in various communication systems.

• The KIPS Transactions:PartB
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• v.13B no.4 s.107
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• pp.369-376
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• 2006

The degradation and its inverse modeling can achieve restoration of corrupted image, caused by scaled digitization and electronic transmission. De-speckle process on the noisy document(or SAR) images is one of the basic examples. Non-linearity of the speckle noise model may hinder the inverse process. In this paper, our study is focused on investigation of the restoration methods for bi-level document image degraded by the impulse noise model. Our study shows that, on bi-level document images, the weighted-median filter and the Lee filter methods are very effective among other spatial filtering methods, but wavelet filter method is ineffective in aspect of processing speed: approximately 100 times slower. Optimal values of the weight to be used in the weighted median filter are investigated and presented in this paper.

• The KIPS Transactions:PartB
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• v.14B no.1 s.111
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• pp.5-12
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• 2007

This paper gives a novel approach that can be represented an image efficiently with its region and shape information together. To do this, we introduced a region-centralized shape descriptor(RCSD) that the size of region only exists at a center point. RCSD consists of circles with three parameters, the distance and the angle between the tenter points, and the diameter, respectively We verified the RCSD parameters to have an information of shape. We can be proved this by reconstructing the shape from the given parameters and evaluated the difference between the its image and the original one. To get this image, we find the estimated points on the contour from the parameters, and connect them by using an interpolation. According to the evaluation, we obtained 88% performance for real images, and showed that it can be used efficiently for representing the binary images. Also we cu make RCSD parameters to be the normalized patterns to have an invariant of its scale or position, and expand them to improve the quality of the performance.

• Journal of Broadcast Engineering
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• v.4 no.1
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• pp.76-85
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• 1999

The degradation of image quality by block loss is more serious in fractal coded images with the error propagation due to mapping from the lost blocks than in DCT coded images. Therefore. a new algorithm is presented for recovering the blocks lost in the transmission through the lossy network as A TM network of the images coded by Jacquins fractal coding. Jacquins fractal code is divided into two layers of header code and main code according to its importance. The key technique of the proposed BLRA (block loss recovery algorithm) is a fractal extrapolation that estimates the lost pixels by using the contractive mapping parameters of the neighboring range blocks whose characteristics are similar to a lost block. The proposed BLRA is applied to the lost blocks in the iteration of decoding. Some experimental results show the proposed BLRA yields excellent performance in PSNR as well as subjective quality.

• Journal of KIISE
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• v.42 no.1
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• pp.7-14
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• 2015

Storage Class Memory(SCM) has been considered as a next-generation storage device because it has positive advantages to be used both as a memory and storage. However, there are significant problems of data consistency in recently proposed file systems for SCM such as insufficient data consistency or excessive data consistency-control overhead. This paper proposes a novel data consistency-control scheme, which changes the write mode for log data depending on the modified data ratio in a block, using a rollback-recovery scheme instead of the Write Ahead Logging (WAL) scheme. The proposed scheme reduces the log data size and the synchronization cost for data consistency. In order to evaluate the proposed scheme, we implemented our scheme on a Linux 3.10.2-based system and measured its performance. The experimental results show that our scheme enhances the write throughput by 9 times on average when compared to the legacy data consistency control scheme.

• Proceedings of the Korean Information Science Society Conference
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• 2012.06d
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• pp.456-458
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• 2012

최근 스마트폰의 개발과 어플리케이션의 다양화로 인하여 OpenAPI을 사용한 'Mashup'의 기술이 많은 곳에서 이용되고 있다. 매쉬업은 2가지 이상의 서비스를 복합하여 사용하므로 요구 목적에 맞는 새로운 형태의 서비스를 만들어 낸다는 장점도 있지만, OpenAPI 정보 제공자에게 종속될 수밖에 없다는 점과, 서비스를 융합하는 과정이 복잡하다는 문제점이 존재한다. 이러한 문제점들은 매쉬업 프로그램 개발과 유지에 있어서 큰 장벽이 된다. 그래서 매쉬업 개발자에게는 자신의 서비스를 만들어 내기 위하여 손쉽게 OpenaAPI에 접근하는 방법과 매쉬업의 문제점을 보완할 수 있는 서비스가 필요하다. 본 논문에서는 매쉬업 서비스의 효율적 관리와 문제점을 보완할 수 있는 통합적 매쉬업 관리 모델에 대해서 다룬다. 통합적 매쉬업 관리 모델은 '선택적 매쉬업'과 '자가 복구 시스템'으로 구성된다. 선택적 매쉬업은 사용자가 원하는 매쉬업 데이터를 얻기 위해서 여러 번 작업을 해야 한다는 번거로움을 간편화하여 효율적 작업처리가 가능하게 하였다. 또한, 자가 복구 시스템은 매쉬업의 단점인 종속적 정보 획득을 보완하고 방지하기 위해서 OpenAPI 수집 에이전트를 통하여 중복된 OpenAPI를 수집, 요구된 매쉬업 정보를 자동 업데이트를 수행하는 기능을 제공한다. 통합적 매쉬업 관리 모델은 매쉬업 사용자에게 편리한 접근 인터페이스 제공하고 종속성이라는 문제점을 해결해 줄 수 있을 것이라고 본다.