• Journal of the Institute of Electronics Engineers of Korea TC
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• v.42 no.9 s.339
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• pp.85-96
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• 2005

A ' Virtual Private Network (YPN) over Internet' has the benefits of being cost-effective and flexible. However, given the increasing demands for high bandwidth Internet and for reliable services in a 'VPN over Intemet,' an IP/GMPLS over DWDM backbone network is regarded as a very favorable approach for the future 'Optical VPN (OVPN)' due to the benefits of transparency and high data rate. Nevertheless, OVPN still has survivability issues such that a temporary fault can lose a large amount of data in seconds, moreover unauthorized physical attack can also be made on purpose to eavesdrop the network through physical components. Also, logical attacks can manipulate or stop the operation of GMPLS control messages and menace the network survivability of OVPN. Thus, network survivability in OVPN (i.e. fault/attack tolerant recovery mechanism considering physical structure and optical components, and secured transmission of GMPLS control messages) is rising as a critical issue. In this Paper, we propose a new path establishment scheme under shared risk link group (SRLG) constraint for physical network survivability. And we also suggest a new logical survivability management mechanism by extending resource reservation protocol-traffic engineering extension (RSVP-TE+) and link management protocol (LMP). Finally, according to the results of our simulation, the proposed algorithms are revealed more effective in the view point of survivability.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.45 no.4
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• pp.31-37
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• 2008

Conventional cooperative communications can attain gain of spatial diversity and path loss reduction because destination node independently received same signal from source node and relay node located between source node and destination node. However, these techniques bring about decreased spectral efficiency with relay node and increased complexity of receiver by using maximal ratio combining (MRC). This paper has proposed cooperative ARQ protocol that can improve the above problems and can get the better performance. This method can increase the spectral efficiency than conventional cooperative communication because if the received signal from source node is satisfied by the destination preferentially, the destination transmits ACK message to both relay node and source node and then recovers the received signal. In addition, if ARQ message indicates NACK relay node operates selective retransmission and we can increase reliability of system compared with that of general ARQ protocol in which source node retransmits data. In the proposed protocol, the selective retransmission and ARQ message are to be determined by comparing log-likelihood ratio (LLR) computation of received signal from source node with predetermined threshold values. Therefore, this protocol don't waste redundant bandwidth with CRC code and can reduce complexity of receiver without MRC. We verified spectral efficiency and BER performance for the proposed protocol through Monte-Carlo simulation over Rayleigh fading plus AWGN.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.24 no.5
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• pp.919-929
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• 2014

Recently, organizational efforts to adopt ISMS(Information Security Management System) have been increasingly mandated and demanded due to the rising threat and the heavier cost of security failure. However there is a serious gap between awareness and investment of information security in a company, hence it is very important for the company to control effectively a variety of information security threats within a tight budget. To phase the ISMS, this study suggests the priorities based on evaluating the Importance of 13 areas for the ISMS by the information security experts and then we attempt to see the difference between importance and investment through the assessment of the actual investment in each area. The research findings show that intrusion incident handling is most important and IT disaster recovery is the area that is invested the most. Then, information security areas with the considerable difference between priorities of importance and investment are cryptography control, information security policies, education and training on information security and personnel security. The study results are expected to be used in making a decision for the effective investment of information security when companies with a limited budget are considering to introduce ISMS or operating it.

• Journal of the Institute of Convergence Signal Processing
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• v.18 no.2
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• pp.55-61
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• 2017

In radio astronomy, high-capacity HDDs are being used to save huge amounts of HDDs in order to record the observational data. For VLBI observations, observational speeds increase and huge amounts of observational data must be stored as they expand to broadband. As the HDD is frequently used, the number of failures occurred, and then it takes a lot of time to recover it. In addition, if a failed HDD is continuously used, observational data loss occurs. And it costs a lot of money to buy a new HDD. In this study, we developed the integrity verification system of the Serial ATA HDD using FirmOS. The FirmOS is an OS that has been developed to function exclusively for specific purposes on a system having a general server board and CPU. The developed system performs the process of writing and reading specific patterns of data in a physical area of the SATA HDD based on a FirmOS. In addition, we introduced a method to investigate the integrity of HDD integrity by comparing it with the stored pattern data from the HDD controller. Using the developed system, it was easy to determine whether the disk pack used in VLBI observations has error or not, and it is very useful to improve the observation efficiency. This paper introduces the detail for the design, configuration, testing, etc. of the SATA HDD integrity verification system developed.

• Proceedings of the Korea Water Resources Association Conference
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• 2015.05a
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• pp.128-128
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• 2015

본 연구는 공적개발원조 사업 중 하나로 개발도상국의 실무자 및 정책결정자의 물 관련 재해위험경감 역량 강화를 위한 교육 훈련 프로그램을 검토하고 개발하는데 목적이 있다. 특히, 물 관련 재해에 대한 구조적, 비구조적 대응방식을 균형있게 논의하고 지방정부 및 관련기관과의 협력, 지역사회기반의 재해경감정책 등 새로운 대응방식관련 교육 프로그램을 검토한다. 2000년-2006년 기간 Emergency Disasters Database (EM-DAT)에 기록된 전 세계 2,163건의 물 관련 재해는 총 29만 명 이상의 인명피해와 4,220억 달러의 재산피해를 초래하였다. 이런 재해는 개발도상국이나 선진국 모두에게 치명적이지만 특히 재해대응역량이 부족한 개발도상국에 막대한 손실을 초래하여 국가개발과 존망에 큰 위협이 되고 있다. 그럼에도 불구하고 대부분의 개발도상국은 재해관리를 간과하여 빈곤의 악순환에서 벗어나지 못하고 있는 실정이다. 본 연구는 2005년 효고행동강령(Hyogo Framework for Action: HFA)의 기본원칙, 2011년 중간평가 검토, 2015년 이후 제시될 새로운 재해위험경감 정책의 틀 속에서 재해위험경감 교육 프로그램을 연구하고자 한다. 이를 위하여 개발도상국 공무원을 대상으로 공적개발원조 프로그램을 운영한 천안의 중앙민방위방재교육원과 일본 고베시의 JICA 등을 방문하여 물 관련 재해 대응의 실질적 개선방향을 모색하였다. 물 관련 재해대응을 위한 교육 프로그램 대상은 실무자와 정책결정자로 설정하고 예방/대비/대응/복구의 유형에 따른 교육과정을 검토한다. 재해 대응 역량강화를 위하여 댐이나 제방 등 홍수위험관리기술과 같은 구조적 방식뿐만 아니라 근본적인 재해위험경감을 위한 홍수위험도 분석과 관리, 도시홍수위험경감계획, 관련 법규제정, 지역홍수위험경감과 민관협력 등과 같은 비구조적 방식에 대한 교육도 포함한다. 이런 측면에서 한국의 경제발전 경험과 물 관련 재해관리 경험을 정책, 사업, 사례와 연관시켜 교육을 진행하고 장단점 비교를 통하여 개발도상국 현지에 적합한 모델을 모색한다. 또한 재해발생시 피해규모를 최소화하게 하는 초동대응을 위해서 행정뿐만 아니라 지역, 시민, 기업 등 다양한 이해 당사자와 주체가 참여하는 종합대책교육을 포함한다. 사회경제발전의 지속을 위해서는 재해에 대한 관리가 매우 중요하다. 특히 인간의 삶에 너무도 익숙하지만 홍수, 가뭄 등으로 치명적인 피해를 야기하는 물 관련 재해에 대응하기 위해서는 물 관리와 관련 재해에 대한 전반적인 이해가 필수적이다. 따라서 한국의 물 관리 경험에 기초한 재해위험경감 교육과 훈련은 개발도상국의 효과적인 재해관리를 가능하게 할 것이다.

• Journal of Korea Water Resources Association
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• v.53 no.12
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• pp.1119-1130
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• 2020

Flood disasters have been recently increasing worldwide due to climate change and extreme weather events. Since flood damage recovery has been conducted as a common coping strategy to flood disasters in the Republic of Korea, it is necessary to predict the regional flood damage costs by rainfall characteristics for a preventative measure to flood damage. Therefore, the purpose of this study is to present the regression functions for human and economic flood damage assessments for the 7 metropolises in the Republic of Korea. A comprehensive regression analysis was performed through the total 48 simple regression models on the two types of flood damage records for human and economic costs over the past two decades from 1998 to 2017 using the four kinds of nonlinear equations with each of the six rainfall variables. The damage assessment functions for each metropolis were finally selected by the evaluation of the regression results with the coefficient of determination and the statistical significance test, and then used for the human and economic flood damage assessments for 100-year rainfall in the 7 metropolises. The results of this study are expected to provide the basic information on flood damage cost assessments for flood damage mitigation measures.

• KIPS Transactions on Computer and Communication Systems
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• v.10 no.4
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• pp.117-122
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• 2021

In recent years, human damage and loss of money due to various disasters such as typhoons, earthquakes, forest fires, landslides, and wars are steadily occurring, and a lot of manpower and funds are required to prevent and recover them. In this paper, we designed and developed a disaster drone system based on artificial intelligence in order to monitor these various disaster situations in advance and to quickly recognize and respond to disaster occurrence. In this study, multiple disaster drones are used in areas where it is difficult for humans to monitor, and each drone performs an efficient search with an optimal path by applying a deep learning-based optimal path algorithm. In addition, in order to solve the problem of insufficient battery capacity, which is a fundamental problem of drones, the optimal route of each drone is determined using Ant Colony Optimization (ACO) technology. In order to implement the proposed system, it was applied to a forest fire situation among various disaster situations, and a forest fire map was created based on the transmitted data, and a forest fire map was visually shown to the fire fighters dispatched by a drone equipped with a beam projector. In the proposed system, multiple drones can detect a disaster situation in a short time by simultaneously performing optimal path search and object recognition. Based on this research, it can be used to build disaster drone infrastructure, search for victims (sea, mountain, jungle), self-extinguishing fire using drones, and security drones.

• The Journal of Bigdata
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• v.8 no.1
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• pp.99-109
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• 2023

Recently, not only in Korea but also around the world, we have been experiencing constant disasters such as typhoons, wildfires, and heavy rains. The property damage caused by typhoons and heavy rain in South Korea alone has exceeded 1 trillion won. These disasters have resulted in significant loss of life and property damage, and the recovery process will also take a considerable amount of time. In addition, the government's contingency funds are insufficient for the current situation. To prevent and effectively respond to these issues, it is necessary to collect and analyze accurate data in real-time. However, delays and data loss can occur depending on the environment where the sensors are located, the status of the communication network, and the receiving servers. In this paper, we propose a two-stage hybrid situation analysis and prediction algorithm that can accurately analyze even in such communication network conditions. In the first step, data on river and stream levels are collected, filtered, and refined from diverse sensors of different types and stored in a bigdata. An AI rule-based inference algorithm is applied to analyze the crisis alert levels. If the rainfall exceeds a certain threshold, but it remains below the desired level of interest, the second step of deep learning image analysis is performed to determine the final crisis alert level.

• Journal of Internet Computing and Services
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• v.16 no.2
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• pp.77-83
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• 2015

Frequent pattern mining, which is one of the major areas actively studied in data mining, is a method for extracting useful pattern information hidden from large data sets or databases. Moreover, frequent pattern mining approaches have been actively employed in a variety of application fields because the results obtained from them can allow us to analyze various, important characteristics within databases more easily and automatically. However, traditional frequent pattern mining methods, which simply extract all of the possible frequent patterns such that each of their support values is not smaller than a user-given minimum support threshold, have the following problems. First, traditional approaches have to generate a numerous number of patterns according to the features of a given database and the degree of threshold settings, and the number can also increase in geometrical progression. In addition, such works also cause waste of runtime and memory resources. Furthermore, the pattern results excessively generated from the methods also lead to troubles of pattern analysis for the mining results. In order to solve such issues of previous traditional frequent pattern mining approaches, the concept of representative pattern mining and its various related works have been proposed. In contrast to the traditional ones that find all the possible frequent patterns from databases, representative pattern mining approaches selectively extract a smaller number of patterns that represent general frequent patterns. In this paper, we describe details and characteristics of pattern condensing techniques that consider the maximality or closure property of generated frequent patterns, and conduct comparison and analysis for the techniques. Given a frequent pattern, satisfying the maximality for the pattern signifies that all of the possible super sets of the pattern must have smaller support values than a user-specific minimum support threshold; meanwhile, satisfying the closure property for the pattern means that there is no superset of which the support is equal to that of the pattern with respect to all the possible super sets. By mining maximal frequent patterns or closed frequent ones, we can achieve effective pattern compression and also perform mining operations with much smaller time and space resources. In addition, compressed patterns can be converted into the original frequent pattern forms again if necessary; especially, the closed frequent pattern notation has the ability to convert representative patterns into the original ones again without any information loss. That is, we can obtain a complete set of original frequent patterns from closed frequent ones. Although the maximal frequent pattern notation does not guarantee a complete recovery rate in the process of pattern conversion, it has an advantage that can extract a smaller number of representative patterns more quickly compared to the closed frequent pattern notation. In this paper, we show the performance results and characteristics of the aforementioned techniques in terms of pattern generation, runtime, and memory usage by conducting performance evaluation with respect to various real data sets collected from the real world. For more exact comparison, we also employ the algorithms implementing these techniques on the same platform and Implementation level.

• The Korean Journal of Nuclear Medicine Technology
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• v.13 no.1
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• pp.51-56
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• 2009

Purpose: Recently, most hospitals are introducing the PACS system and use of the system continues to expand. But small-scaled PACS called MicroPACS has already been in use through open source programs. The aim of this study is to prove utility of operating a MicroPACS, as a substitute back-up device for conventional storage media like CDs and DVDs, in addition to the full-PACS already in use. This study contains the way of setting up a MicroPACS with open source programs and assessment of its storage capability, stability, compatibility and performance of operations such as "retrieve", "query". Materials and Methods: 1. To start with, we searched open source software to correspond with the following standards to establish MicroPACS, (1) It must be available in Windows Operating System. (2) It must be free ware. (3) It must be compatible with PET/CT scanner. (4) It must be easy to use. (5) It must not be limited of storage capacity. (6) It must have DICOM supporting. 2. (1) To evaluate availability of data storage, we compared the time spent to back up data in the open source software with the optical discs (CDs and DVD-RAMs), and we also compared the time needed to retrieve data with the system and with optical discs respectively. (2) To estimate work efficiency, we measured the time spent to find data in CDs, DVD-RAMs and MicroPACS. 7 technologists participated in this study. 3. In order to evaluate stability of the software, we examined whether there is a data loss during the system is maintained for a year. Comparison object; How many errors occurred in randomly selected data of 500 CDs. Result: 1. We chose the Conquest DICOM Server among 11 open source software used MySQL as a database management system. 2. (1) Comparison of back up and retrieval time (min) showed the result of the following: DVD-RAM (5.13,2.26)/Conquest DICOM Server (1.49,1.19) by GE DSTE (p<0.001), CD (6.12,3.61)/Conquest (0.82,2.23) by GE DLS (p<0.001), CD (5.88,3.25)/Conquest (1.05,2.06) by SIEMENS. (2) The wasted time (sec) to find some data is as follows: CD ($156{\pm}46$), DVD-RAM ($115{\pm}21$) and Conquest DICOM Server ($13{\pm}6$). 3. There was no data loss (0%) for a year and it was stored 12741 PET/CT studies in 1.81 TB memory. In case of CDs, On the other hand, 14 errors among 500 CDs (2.8%) is generated. Conclusions: We found that MicroPACS could be set up with the open source software and its performance was excellent. The system built with open source proved more efficient and more robust than back-up process using CDs or DVD-RAMs. We believe that the operation of the MicroPACS would be effective data storage device as long as its operators develop and systematize it.