그룹키를 이용한 보안 멀티캐스트 시스템에서 최소 비용을 위한 Rekey Interval 할당에 관한 연구

이구연,이용,Lee, Goo-Yeon,Lee, Yong 대한전자공학회 2003 電子工學會論文誌-TC (Telecommunications) Vol.40 No.1

본 논문에서는 그룹키를 이용하는 보안 멀티캐스트 환경에서 그룹키 노출로 인한 정보손실과 그룹키 재분배의 과정에 대하여 연관지어 설명한다. 또한 손실된 정보에 대한 비용과 키 갱신에 소요되는 비용의 과제를 결합하여 최소의 비용을 갖는 최적의 rekey interval을 분석한다. 본 분석의 결과를 이용하면 그룹키 재분배에 있어서 비용적인 면을 효율성의 척도로 하여, 회원수, 회원의 보안 능력 및 탈퇴율등을 반영하여 rekey interval을 구함으로서 최소비용으로 그룹을 관리할 수 있다. 이러한 효율적인 rekey interval 할당에 대한 연구는 지금까지 크게 중요시되지 않던 부분이었으나 rekey interval 할당에 대한 문제를 현재보다 개선하고 보완한다면, 보안 멀티캐스트 그룹의 활강성과 활용성을 증가시킬 수 있을 것이다. In this paper, we investigate a rekey mechanism for a secure multicast group communications and relate the mechanism to the loss of information from group key exposal. We also combine cost for the information loss and cost for group key updates and analyze the optimum rekey interval. Using the results of the analysis in this paper, we can manage a secure multicast group efficiently with the minimal cost on the bases of number of group members, each member's security level and withdrawal rates.

Design and Implementation of a Peer-to-Peer Data Sharing Scheme for Closed User Group with Security and Flexibility

이구연(Goo-Yeon Lee),이용(Yong Lee),김화종(Hwa-Jong Kim),정충교(Choong-Kyo Jeong),이동은(Dong-Eun Lee) 한국정보보호학회 2005 정보보호학회논문지 Vol.15 No.4

We propose and implement a flexible secure peer-to-peer(P2P) file sharing scheme which can be used for data sharing among closed user group (CUG) members. When a member wants to share data, notification messages are sent to the members with whom the member wants to share data. Each notification message includes one-time password encrypted with the receiver's public key. A member who received the notification message can download the data by using the one-time password. The proposed scheme provides selective sharing, download confirmation and efficient storage management. In terms of security, the proposed scheme supports authentication, entity privacy, replay attack protection and disguise prevention. We also implement the proposed system and find that the system is very useful among P2P service of closed user groups.

무선 애드 혹 네트워크의 최대 전송 용량 분석

이구연(Lee, Goo-Yeon),이용(Lee, Yong) 강원대학교 산업기술연구소 2012 産業技術硏究 Vol.32 No.1

In this paper, we investigate maximum transmission capacity of wireless ad-hoc networks. In the investigation, we consider a network topology with regularly located nodes. For the topology, we investigate the maximum transmission capacity with RTS/CTS medium access protocol, and next, we study the maximum transmission capacity without the protocol. We see that the results of our study overall follows the result of Gupta and Kumar s research.

반응표면분석법을 이용한 반죽물성의 모델링 및 최적화

이구연 ( Kooyeon Lee ),최광석 ( Gwkang Seok Choi ),김태우 ( Tae Woo Kim ),조관형 ( Kwan Hyung Cho ),강동진 ( Dongjin Kang ),김성태 ( Sung Tae Kim ),장동진 ( Dong-jin Jang ) 한국산업식품공학회 2017 산업 식품공학 Vol.21 No.2

이 연구에서는 표면반응분석법의 기법 중 하나인 박스-벤켄법을 사용하여 밀가루 반죽의 물리적 특성을 예측하고 조절 할 수 있는 방법을 연구하였다. 반죽의 주요한 물리적 특성으로는 경도, 응집성 그리고 탄력성을 선정하였고 주요한 영향인자들로서 물, 이스트 그리고 발효시간을 선정한 후에 영향인자들과 물리적 특성들의 관계를 나타내는 모델링을 수행하였다. 얻어진 모델을 통하여 설계공간을 설정하고 제조를 위한 최적조건과 예상 결과를 계산할 수 있었으며, 예측된 결과와 실제 결과들은 모두 90% 이상의 정확성을 나타내었다. 결론적으로 표면반응분석법에 의한 최적화 기법은 식품산업에서 반죽특성과 최종제품의 품질을 예측하는데 폭넓게 활용될 수 있을 것이다. The purpose of this study was to optimize dough properties using response surface methodology (RSM) and to demonstrate the performances of dough prepared under optimized conditions. Dough mixed with yeast, margarine, salt, sugar and wheat flour was prepared by fermentation process. Hardness, cohesiveness and springiness of dough were selected as critical quality attributes. The critical formulations (yeast and water) and process (fermentation time) variables were selected as critical input variables based on preliminary experiment. Box-Behnken design (BBD) was used as RSM. As a result, the quardratic, the squared and the linear model respectively provided the most appropriate fit (R²>90) and had no significant lack of fit (p>0.05) on critical quality attributes (hardness, cohe-siveness and springiness). The accurate prediction of dough characteristics was possible from the selected models. It was confirmed by validation that a good correlation was obtained between the actual and predicted values. In con-clusion, the methodologies using RSM in this study might be applicable to the optimization of fermented foods con-taining various wheat flour and yeast.

IoT 환경에서 GDPR에 부합하는 개인정보수집 동의 절차

이구연(Goo Yeon Lee),방준일(Junil Bang),차경진(Kyung Jin Cha),김화종(Hwa Jong Kim) 한국정보기술학회 2019 한국정보기술학회논문지 Vol.17 No.5

Many IoT devices like sensors lack screen and input devices, thus making them hard to meet the consent conditions that GDPR requires. This is acting as a legal barrier for further advancement in the business field. In this paper, we designed the process for consent of personal information collection that meets the legal conditions. In this design, user’s personal data is received in an encrypted form by data collecting server first. The encrypted personal data can be decrypted after associating with user agent based on the consent procedure of the collection of personal information. During the consent procedure, user agent understands the privacy policy about personal information collection and offers the key to decrypt the data. This kind of personal information collection agreement procedure will satisfy the transparent and freely given consent requirements of GDPR. Thus, we can speculate from here that the proposed procedure will contribute to the evolution of IoT business area dealing with personal information.

택시의 운행 데이터에 기반한 최적의 운행 속도 분석

이구연(Goo Yeon Lee),김화종(Hwa Jong Kim) 한국디지털콘텐츠학회 2015 한국디지털콘텐츠학회논문지 Vol.16 No.2

In this paper, we analyze the optimum moving speed of taxi for maximum revenue. In the analysis, we vary taxi speed from 5km/h through 80km/h to see how revenue of a taxi varies applying the practical gas mileage of LPG taxi and taxi fare system in Korea. From the results of the analysis, we see that the probability that a taxi meets passengers goes high as taxi speed gets fast, however the fuel cost also goes up. We also obtain the optimum speed for the maximum revenue according to passenger distribution while varing moving speed.

대학 학사정보시스템의 클라우드 컴퓨팅을 위한 최적용량 분석

이구연(Goo Yeon Lee),최황규(Hwang Kyu Choi),최창열(Chang Yeol Choi),장민(Min Jang),윤재구(Jae Ku Yoon) 한국디지털콘텐츠학회 2014 한국디지털콘텐츠학회논문지 Vol.15 No.3

Recently, cloud computing has been affecting academic information system buildup. When university academic affairs information system is designed with cloud computing, it is very important to estimate the adequate processing capacity for the cloud computer taking into account a waste of resources and the quality of service. Cloud computers processing capacity to meet the quality of service expected by users should be predicted based on users transaction patterns and resource requirements characteristics. In this paper, we analyze actual traffic patterns occurring in university academic affairs business and propose a method to calculate the optimal processing capacity for cloud computer to satisfy the given average response time. To justify our research, we apply the research results to a real university academic affairs business case and obtain the optimal processing capacity for the integrated academic affairs business.

전송시간의 변화가 큰 네트워크에서 이레이저 코딩을 적용한 긴급 데이터 전송 방법 및 성능 분석

이구연(Goo Yeon Lee),이용(Yong Lee) 한국디지털콘텐츠학회 2014 한국디지털콘텐츠학회논문지 Vol.15 No.2

In this paper, we focus on end-to-end transfer delay improvement by using erasure coding when delivering expediting message consisting of M packets in networks with high coefficient of variation of transfer time. In the scheme, M packets are divided into b groups with each having g packets. Each group is erasure coded with additional r packets and transmitted. Since the first arrived g packets among g+r packets completes the delivery of the group, the delivery time of the expediting message is reduced. For the scheme, we investigate the optimum group size and number of redundancy packets considering delivery delay reduction and additional transmission cost caused by using erasure coding. From the results of the investigation, we see that the proposed scheme is effective in networks having high variability of transfer time and would be very useful and practical especially for the case that expedited deliveries of messages are needed.

전송시간의 변화가 큰 네트워크에서 네트워크 코딩을 적용한 전송 지연시간 개선 방법 및 성능 분석

이구연(Goo Yeon Lee),이용(Yong Lee) 대한전자공학회 2012 전자공학회논문지 Vol.49 No.11

본 논문에서는 전송시간의 변화가 큰 네트워크 환경에서 네트워크 코딩을 이용한 종단간 메시지 지연 단축 스킴을 제안한다. 제안된 스킴에서는 메시지를 여러개의 패킷(g개의 패킷)으로 분할하고, 이에 대하여 네트워크 코딩을 수행함으로서 리던던시 패킷(r개의 패킷)을 포함하여 만들어진 패킷들(g+r개의 패킷)을 전송한다. g+r개의 패킷 중에서 g개의 패킷이 도착하면 메시지가 복구되므로 전체적인 메시지 전송지연은 단축된다. 일반적으로 네트워크는 전송하는 패킷의 최대 크기 제한을 두고 있으므로, 이러한 환경에서 본 논문에서 제안한 스킴에서의 지연 단축 효과 및 전송 비용을 고려하여 최적의 패킷 분할 수 및 리던던시 패킷의 수에 대한 분석을 수행한다. 분석 결과로부터 제안된 스킴은 전송시간의 변화가 큰 네트워크에서 큰 효과를 내며, 특히 긴급한 메시지의 전송이 필요할 때 유용함을 알 수 있다. In this paper, we focus on end-to-end transfer delay improvement by using network coding and propose a scheme where a message is divided into several packets which are network coded generating additional redundancy with the results that the number of transmitted packets increases. In networks with high coefficient of variation of transfer time, increased number of packets could reduce the transfer time of the message to a destination. For the proposed scheme, we investigate the optimum number of divided packets and redundancy considering transfer delay reduction and additional transmission cost caused by using network coding under the restriction of maximum transmission packet size. From the results of the investigation, we see that the proposed scheme is effective in networks having high variability of transfer time and would be very useful and practical especially for the case that expedited deliveries of messages are needed.

캠퍼스내 레거시 웹서버 통합 운영을 위한 클라우드 컴퓨팅의 최적용량 및 전환이익 분석

이구연(Goo Yeon Lee),최창열(Chang Yeol Choi),최황규(Hwang Kyu Choi),장민(Min Jang),윤재구(Jae Ku Yoon) 한국디지털콘텐츠학회 2014 한국디지털콘텐츠학회논문지 Vol.15 No.2

Cloud computing helps users to save a significant amount of cost that is related to infrastructure investment, management, and maintenance. In this paper, we study the conversion planning from campus legacy web servers into an integrated cloud computing web server system. We also analyze the conversion profit when campus web servers are integrated into a cloud computer. We first investigate the cost of legacy system model of campus web servers operated by individual laboratories, departments, institutes and so on. Next, we set up a cloud computer model for the integrated web services meeting the same performance requirements. Then, we derive the conversion profit. From the result of the derivation, we see that the conversion can be effectively applied to and adopted by mid or large sized campuses and similar institutions that provide web services.