• Journal of KIISE
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• v.43 no.3
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• pp.314-326
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• 2016

Some process algebras were applied to enterprise business modelling for formal specification and verification. ${\pi}$-calculus and mobile ambient can be considered for the distributed and mobile, especially to represent the movements of distributed real-time business processes. However there are some limitations to model the movements: 1) ${\pi}$-calculus passes the name of port for indirect movements, and 2) mobile ambient uses ambient to synchronize asynchronous movements forcefully. As a solution to the limitations, this paper presents a new process algebra, called ${\delta}$-calculus, to specify direct and synchronous movements of business processes over geo-temporal space. Any violation of safety or security of the systems caused by the movements can be indicated by the properties of the movements: synchrony, priority and deadline. A tool, called SAVE, was developed on ADOxx metamodelling platform to demonstrate the concept.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.7 no.5
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• pp.1291-1312
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• 2013

Cloud computing changes the service models of information systems and accelerates the pace of technological innovation of consumer electronics. However, it also brings new security issues. As one of the important foundations of various cloud security solutions, entity authentication is attracting increasing interest of many researchers. This article proposes a layered security architecture to provide a trust transmission mechanism among cloud systems maintained by different organizations. Based on the security architecture, four protocols are proposed to implement mutual authentication, data sharing and secure data transmission in federated cloud systems. The protocols not only can ensure the confidentiality of the data transferred, but also resist man-in-the-middle attacks and masquerading attacks. Additionally, the security properties of the four protocols have been proved by S-pi calculus formal verification. Finally, the performance of the protocols is investigated in a lab environment and the feasibility of the security architecture has been verified under a hybrid cloud system.

• Proceedings of the Korea Information Processing Society Conference
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• 2000.04a
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• pp.133-136
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• 2000

자바에서 또한 이러한 병행성 프로그램을 지원하기 위한 다양한 언어적 지원과 병행적인 요건을 지원하고 있다. Thread class지원, Synchronized 예약어, 상호협동 관계를 표현하기위한 wait(), notify(), notifyAll() 메서드 , monitor 메커니즘등을 지원하고 있다. 하지만 이는 아주 저 수준의 지원형태이며 여러 가지 문제점을 야기할 수 있다. 이에 대해 병행적 이론의 정수라고 할 수 있는 pi-calculus의 이론과 기법을 도입하여 새로운 시각으로 병행성 프로그래밍에 대한 접근을 하고자 한다. 여기에 실용적으로 많이 사용되고 발전되어온 자바에서 적용하고자 한다. pi-calculus에 기반한 pict를 모델로 하여 pict에서 지원하는 아주 명료한 연산자와 current object를 도입함으로써 보다 표현력과 확장성, 검증성이 뛰어난 고 수준 자바 라이브러리를 설계하고자 한다.

• Journal of Periodontal and Implant Science
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• v.24 no.3
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• pp.458-471
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• 1994

To evaluate the periodontal status of Korean adults, 3,988 adults(20-69 years old) who lived in Kwangju, Chonnam, Taegu, and Kyungbuk districts were periodontally examined by plaque index(PI), calculus index(CI), gingival index(GI), periodontal disease index (PDI), and papillary bleeding index(PBI). The periodontal examination charts were grouped according to age and sex. And subsequently 200 periodontal examination charts in each age group were randomly selected according to sex. The differences of the indices among age groups and those between male and female in each age group were statistically analyzed by Chi-Square test. In PI, CI, GI, PDI, and PBI, there was no statistical significance in the difference between male and female in each age group(p>0.05). In male, PI of 60s age group($1.44{\pm}0.68$) was significantly higher than that of any age group(p<0.05), and in female PI of 20s age group($0.86{\pm}0.39$) was significantly lower than that of any other age group(p<0.05). CI of 60s age group in both male($1.67{\pm}0.70$) and female($1.63{\pm}0.91$) was significantly higher than that of any age group(p<0.05). GI of 20s age group in both male($0.85{\pm}0.66$) and female($0.67{\pm}0.60$) was significantly lower and GI of 60s age group in both male($1.37{\pm}0.60$) and female($1.44{\pm}0.84$) was higher than that of any age group(p<0.05). PDI in male was the lowest in 20s age group($0.70{\pm}0.73$), and was the highest in 60s age group($4.93{\pm}1.96$) (p<0.05). In female PDI of 20s age group($0.71{\pm}0.74$) was significantly lower than that of any age group(p<0.05). In male PBI of 20s age group($0.38{\pm}0.31$) was significantly lower than that of any age group(p<0.001). PBI in female was the lowest in 20s age group($0.35{\pm}0.30$) (p<0.001), and was the highest in 60s age group($1.09{\pm}0.76$) (p<0.05). The data insist that all the young populations of 20s age group should be interested in routine check for early diagnosis and prevention of periodontal disease, and a special education program of periodontal health care for young generation must be prepared, and the periodic recall check system for periodontal examination of middle age group must be supported by government.