• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2002.05a
• /
• pp.836-839
• /
• 2002

This paper describes the selective Boolean operations on non-manifold geometric models whose union and subtraction operations are communicative. These operations guarantee the same resulting shape in spite of change of the order of Boolean operations, and the integrity of the model for omission of some features. In addition, a B-rep model for a modified modeling history is obtained in a short time, as no boundary evaluation is necessary. These features enable easy implementation of multi-resolution representation of B-rep models.

• Proceedings of the Korea Institutes of Information Security and Cryptology Conference
• /
• 2003.07a
• /
• pp.307-311
• /
• 2003

Okeya-Sakurai는［12］에서 단순한 형태의 랜덤한 덧셈-뺄셈 체인의 대응방법［14］은 SPA공격에 취약함을 보였다. 그러나 그들의 분석 방법은 복잡한 형태［14］에는 적용되지 않는다. 본 논문에서는 Okeya-Sakurai의 공격 알고리듬에 두 가지 잠재된 문제가 있음을 보인다. 또한［12,15］와는 다른 강하고 견고한 새로운 공격 알고리듬을 제안한다. 본 논문에서 제안하는 공격 알고리듬을 사용하면 복잡한 형태의 랜덤한 덧셈-뺄셈 체인［14］또한 완벽하게 분석된다. 본 논문의 결과를 표준에서 제안된 163비트로 실험한 결과 단순한 형태에서는 20개의 AD수열로 대략 94%의 확률로 공격이 성공하며 30개의 AD수열로는 대략 99%의 확률로 공격이 성공한다. 또한, 복잡한 형태에서는 40개의 AD수열로 94%의 확률로 70개의 AD수열로는 99%로의 확률로 공격이 성공한다.

• Proceedings of the KIEE Conference
• /
• 1995.07b
• /
• pp.682-684
• /
• 1995

The most effective way to improve the performance of a fuzzy controller may be to optimize look-up values. Look-up values are derived from processes used input-output scale factors, membership functions, rule base, fuzzy inference method and defuzzification. It is powerful way to modify or organize look-up table values. In this paper, We propose the look-up values self-organizing fuzzy controller(LSOFC). We use the plus-minus tuning method(PMTM), scanning values through the processes of addition and subtraction. We show the efficiency of this LSOFC by the results of simulation for nonlinear time-varying plant with unmodelled dynamics.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2006.11a
• /
• pp.173-176
• /
• 2006

The one of the commonly reported failure mode of the RC beam strengthened with FRP was caused by the separation of the concrete cover, so called delamination. Therefore, ACI440 recommended that concrete cover delamination can be prevented in strengthened beams if bond length of FRP composite be exteneded over a point of cracking moment. In this study, the failure mode and the flexural performance of RC beam with different bond length of FRP are estimated. Each bonded length is calculated based on the point of cracking moment with addition or subtraction of specific length(=150mm). The results of this study show that mid-span debonding occurs in the specimen strengthened with CFRP strips which are bonded over the point of cracking moment, while concrete cover deliamination occurs at the termination point of CFRP in the specimen with less bonded length than the point of cracking moment region.

• Korean Journal of Child Studies
• /
• v.36 no.4
• /
• pp.229-242
• /
• 2015

The purpose of this study was to investigate young children's nonsymbolic arithmetic ability according to task difficulty. The participants in this study comprised 43 2-year-old children and 48 4-year-old children recruited from 5 childcare centers located in Seoul, Korea. All tasks were composed of comparison, addition, subtraction, multiplication and division tasks. In addition, each arithmetic task varied with the ratio of the two quantities; low level(1:2), middle level(2:3), high level(4:5). The results revealed that 2 & 4-year-old children could perform a large numerical range of nonsymbolic arithmetic tasks without influences from previously learned mathematics. This finding suggests that children have a degree of numerical capacity prior to symbolic mathematics instruction. Furthermore, children's performance on nonsymbolic arithmetic tasks indicated the ratio signature of large approximate numerical representation. This result implies that large approximate numerical representation can be used in arithmetical manipulations.

• Transactions of Materials Processing
• /
• v.6 no.5
• /
• pp.400-407
• /
• 1997

Geometric mapping technique has been used to find the shape of initial blank for sheet forming. The method was chosen because of its simplicity and numerical efficiency. Error in blank shape were measured along deformation path by FE analysis of forming. Blank shape was modified by volume additionaddition/Subtractiontraction method with taking with taking into account of deformation path. Modified blank shape shows an acceptable result, showing the current method can be an useful tool for predicting blank shape in the practical application. More test will be done to verify the validity of the method.

• Korean Journal of Optics and Photonics
• /
• v.10 no.5
• /
• pp.396-400
• /
• 1999

In the fiber-optic gyroscope employing a high-power erbium-doped fiber source, the source excess noise was subtracted from the gyro output through a single processing to improve the gyroscope sensitivity. As the result, we obtained the reduction of noise by 13.5 dB (electrical) which was measured from the noise floor spectrum when the gyro was modulated with the depth of 1.8 rad. In addition, the random walk coefficient of the gyro output was reduced by a factor of 4~5.

• Education of Primary School Mathematics
• /
• v.11 no.2
• /
• pp.95-103
• /
• 2008

The 7th national mathematics curriculum was revised in 2007. According to the revision curriculum, new texts and guides are developed and will come into effect for elementary and secondary school in 2009. Some contents are shifted and also newly added at the revision curriculum. This paper analyzed the gap between the revision and the 7th national mathematics curriculum based on the shifts in contents, and investigated on the difficulties that some graders probably will undergo owing to shifting the contents between grades. As a result, several important problems were found in some graders between the revision and the 7th national mathematics curriculum. In particular, some graders could not have a chance to learn some mathematical concepts without another lesson plans. For some graders, special lesson plans and supplementations are required. The brief summary of these supplementations as follows: ⅰ) For entering students in 2005, the supplementations about equations and direct proportion and inverse proportion should be needed at the 6th grade in 2010 or at the 7th grade in 2011. ⅱ) For entering students in 2006, the supplementations about estimations and correspondence should be needed at the 4th grade in 2009 or at the 5th grade in 2010. And the supplementations about the relation of fractions and decimals and the ratio should be needed at the 5th grade in 2010. ⅲ) For entering students in 2007, the supplementations about the addition and subtraction of time using second unit and the addition and subtraction of weight should be needed at the 3th grade in 2009 or at the 4th grade in 2010.

• Journal of Elementary Mathematics Education in Korea
• /
• v.22 no.2
• /
• pp.183-198
• /
• 2018

In this paper, I theoretically considered joining and separating activities and revisited the textbooks from 7 countries and Korean mathematics textbooks from 5th revised curriculum to 2015 revised curriculum to find implication for the treatment of 0 in the joining and separating activities. The 'joining' has definition and properties similar to addition, but the 'separating'is difficult to define and is not considered to have properties similar to subtraction. In the sense of computation, joining and separating can be seen as' part-part-to-whole' situations, but are just part of the addition and subtraction situations. The analysis of textbooks from 7 counties showed that Singapore and Malaysia textbooks already studied zero and then included it in joining and separating activities, but other countries did not include it as joining and separating activities. The textbooks of South Korea have consistently suggested not to include zero, but teacher's guide has shown that there is a little consistency in the treatment of zero. As a conclusion, I suggested that it was necessary to propose a proper context of the situation in order to introduce joining and separating without including 0 in terms of student level and to propose that a more consistent presentation of zero handling in the teaching in the teacher's guide.

• KIEAE Journal
• /
• v.11 no.5
• /
• pp.55-67
• /
• 2011

The purpose of this research is to find applicable design characteristics and methods of communal spaces in vertical urban multi-family housing. With this goal, several overseas' multi-family housing projects are selected and their communal spaces are identified. The design characteristics of the communal spaces are analyzed with a special focus on the territories such as an individual unit boundary, building interior and exterior boundary. In terms of the framework for analysis, territoriality, openness, and unique characteristics are reviewed. As a result, the communal spaces are created using various spatial composition methods such as addition, subtraction, connection, extension, accumulation, and isolation. The communal space programs are integrated in plans and sections throughout the buildings. Visual openness and connection with surrounding urban environments are articulated by void spaces, transparent and translucent building materials, green spaces, and applications of graphical images. Communal identities and aesthetics are emphasized by unique building forms and space arrangements. The uses of finish materials, colors, objects, and images add strong characters to the communal spaces. For a further research, it is necessary to combine a design method study with residents' behaviors and community interactions.