• Journal of the Optical Society of Korea
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• v.20 no.2
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• pp.283-290
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• 2016

This study presents an 8x four-group inner-focus zoom lens with one-moving group for a compact camera by use of a focus tunable lens (FTL). In the initial design stage, we obtained the powers of lens groups by paraxial design based on thin lens theory, and then set up the zoom system composed of four lens modules. Instead of numerically analytic analysis for the zoom locus, we suggest simple analysis for that using lens modules optimized. After replacing four groups with equivalent thick lens modules, the power of the fourth group, which includes a focus tunable lens, is designed to be changed to fix the image plane at all positions. From this design process, we can realize an 8x four-group zoom system having one moving group by employing a focus tunable lens. The final designed zoom lens has focal lengths of 4 mm to 32 mm and apertures of F/3.5 to F/4.5 at wide and tele positions, respectively.

• Proceeding of Spring/Autumn Annual Conference of KHA
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• 2008.11a
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• pp.241-246
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• 2008

The research objective of this thesis aims to utilize the history and culture of cities as resources and to solve the problems of modern urban environment which can produce non-personality in the age of globalization. This study deals the Sustainable Urbanism and Architectural System in the Historical city ; First, Historic resources and its spatial characteristics. Second, reused resources and remodeling of existing building. Third, Sustaiabl design component and management process. Historic resource are not only a cultural and spatial aspects but also it have potential importance in environmental aspects. Sustainable urbanism and architectural environment are cultural resource and it can be enhanced by long term established spatial orders. In order to keep the order, rehabilitation, reuse, remodeling of urban space should be managed by various participations which concerned with the city and urban architecture. That can be say systematic approach for the sustainable environment.

• Transactions on Control, Automation and Systems Engineering
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• v.3 no.4
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• pp.242-249
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• 2001

In this paper, the open-loop state response of the two-time-scale systems by unified approach using the $\delta$-operator is presented with an example of the aircraft longitudinal dynamics. First, the $\delta$-operator system unifies both the continuous system and the discrete system simultaneously, and the $\delta$-operator approach improves the finite word-length characteristics. This saves more computing time than that of the discrete system. Second, the singular perturbation method by block diagonalization reduces the sizes and orders of the systems. This also reduces the floating-point operations (flops). The advantage of those two approaches is shown by comparing our results with the earlier ones in the illustrative example of the longitudinal motion of F-8 aircraft.

• ETRI Journal
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• v.28 no.6
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• pp.745-760
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• 2006

In this paper, we particularly deal with no $F_p$-rational two-torsion elliptic curves, where $F_p$ is the prime field of the characteristic p. First we introduce a shift product-based polynomial transform. Then, we show that the parities of (#E - 1)/2 and (#E' - 1)/2 are reciprocal to each other, where #E and #E' are the orders of the two candidate curves obtained at the last step of complex multiplication (CM)-based algorithm. Based on this property, we propose a method to check the parity by using the shift product-based polynomial transform. For a 160 bits prime number as the characteristic, the proposed method carries out the parity check 25 or more times faster than the conventional checking method when 4 divides the characteristic minus 1. Finally, this paper shows that the proposed method can make CM-based algorithm that looks up a table of precomputed class polynomials more than 10 percent faster.

• Journal of the Korean Home Economics Association
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• v.40 no.1
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• pp.1-21
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• 2002

The purposes of this study is to classify retiree's job, leisure, and family attitude; to identify the characteristics of each attitude types; and to examine the retirement adaptation level of each attitude type. The major findings of the study are as follows: First, four attitude types can be categorized: 'the job involved attitude type', 'the total positive attitude type', 'the leisure positive attitude type', and 'the total negative attitude type'. Second, the result of the discriminant analysis shows that 'the job-family experience before retirement and number of unmarried children' element was the most crucial in classifying the retiree's attitude. And 'the retirement reception and individual resource element' was in orders of discrimination power Third, 'the total positive attitude type' is the highest level of retirement adaptation.

• The Journal of Korean Medical History
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• v.21 no.1
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• pp.83-88
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• 2008

Jejoongshinpyeon was published in 1799 by 康命吉 upon receiving orders from the king. This book is a critical accedence of Treasured Mirror of Oriental Medicine and aims to enunciate summarized medical knowledge. Through examining citation methods in Jejoongshinpyeon, the following conclusions could be reached: First, citation methods displayed in Jejoongshinpyeon is largely based on Treasured Mirror of Oriental Medicine. Second, the specific method of citing Treasured Mirror of Oriental Medicine involves collecting and describing annotations from different titles.. Third, Jejoongshinpyeon cites other medical texts by making additions to symptoms or prescriptions not included in Dongeuibogam.

• The Korean Journal of Malacology
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• v.7 no.1
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• pp.58-65
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• 1991

A study on the distribution and community structure of the benthic molluscan shells of the southern coastral area in Cheju Island was carried out from August 1990 to July 1991. The benthic molluscan shells collected and identified from 8 stations were composed of 3 classes, 7 orders, 22 families and 59 species. The number of appearance species from station 1 to station 8 were 22, 35, 32, 26, 28, 24, 32 and 31 species respectively. the first dominant species of the upper intertidal zone of the 8 stations were Nodilittorina exigua, those of the middle zones were Monodonta neritoides from st.1 to St.5, but the second dominant species were not uniftom at ach station.

• Korean journal of applied entomology
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• v.32 no.2
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• pp.168-175
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• 1993

This study investigated the composition and distribution of the soil microarthropods community in plantations of the Korean pine(Pinus Koraiensis SIEB. et ZUCC, the sudong area, Namyangju-gun, Korea) , which had been planted in different years. The soil samples intended to collect soil animals were taken monthly from June 1988 to July 1989. The composition of soil microarthropods community included Arachnida, Chilopoda, Insecta, Collembola, Diplopoda, Crustacea, and Symphyla. The Acarina were composed of 82.4% of Cryptostigmata, 8.0% of Mesostigmata, 7.9% of nymphs, and 1.7% of others. The Insecta included six orders including Hymenoptera(65.8%) and Diptera(13.9%). Population densities increased from when the plantations were first established until the planting were 25 years old, after which they declined. Population densities of the soil microarthropods were highest in July and lowest in January. The Collembola/Acarina ratio is 0.16 overall, and was highest in January and lowest in August.

• Proceedings of the KSR Conference
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• 2007.05a
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• pp.594-599
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• 2007

According to separation policy between rail infrastructure and operation, the National Railroad Administration was converted to Korea Railroad Cooperation on Jan, 2005. That makes railway service assessment regarded as essential. About this matter, Section 15 of the Framework Act on Rail Industry Development and section 26 of the Rail Business Act shows that the railway service assessment should be conducted every 2 years. The government can officially announce the result and give orders operation company to improve service level. In the first railway service assessment in 2006, the principal railroad lines and stations were investigated. Rail supply service index and customer satisfaction index are introduced. It includes service items of supply, reliability, convenience, safety and customer satisfaction. This study presents the contents of 2006 rail service assessment. Some points of assessment which should be improved are analyzed as well.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• v.8 no.1
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• pp.11-30
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• 2004

Access Control is one of essential branches to provide system's security. Depending on what standards we apply, in general, there are Role-based access control, History-based access control. The first is based on subject's role, The later is based on subject's history. In fact, RBAC has been implemented, we are using it by purchasing some orders through the internet. But, HBAC is so complex that there will occur some errors on the system. This is more and more when HBAC is used with other access controls. So HBAC's formalization and model which are general enough to encompass a range of policies in using more than one access control model within a given system are important. To simplify these, we design the mathematical model called non-access structure. This Non-access structure contains to historical access list. If it is given subjects and objects, we look into subject grouping and object relation, and then we design Non-access structure. Then we can determine the permission based on history without conflict.