• 대한수학회보
• /
• 제60권6호
• /
• pp.1477-1496
• /
• 2023

A class of normalized univalent functions f defined in an open unit disk of the complex plane is introduced and studied such that the values of the quantity zf'(z)/f(z) lies inside the evolute of a nephroid curve. The inclusion relations of the newly defined class with other subclasses of starlike functions and radius problems concerning the second partial sums are investigated. All the obtained results are sharp.

• Kyungpook Mathematical Journal
• /
• 제58권1호
• /
• pp.117-135
• /
• 2018

The orthogonal trajectories of the first tangents of the curve are called the involutes of x. The hyperspheres which have higher order contact with a curve x are known osculating hyperspheres of x. The centers of osculating hyperspheres form a curve which is called generalized evolute of the given curve x in n-dimensional Euclidean space ${\mathbb{E}}^n$. In the present study, we give a characterization of involute curves of order k (resp. evolute curves) of the given curve x in n-dimensional Euclidean space ${\mathbb{E}}^n$. Further, we obtain some results on these type of curves in ${\mathbb{E}}^3$ and ${\mathbb{E}}^4$, respectively.

• 한국지능정보시스템학회:학술대회논문집
• /
• 한국지능정보시스템학회 2000년도 춘계정기학술대회 e-Business를 위한 지능형 정보기술 / 한국지능정보시스템학회
• /
• pp.165-173
• /
• 2000

Some people think that the Internet is a tool of making the current market as a perfect competition market and that the business model of selling products or services is not attractive. But research of this issue propose that the Internet give us new challenge of business. The objective of this study is to analyze the properties of Internet and Internet business and to evolute the Internet business model of selling products or services and to suggest survival strategies in fierce competition circumstances.

• 대한수학회논문집
• /
• 제38권2호
• /
• pp.589-598
• /
• 2023

Magnetic curves are the trajectories of charged particals which are influenced by magnetic fields and they satisfy the Lorentz equation. It is important to find relationships between magnetic curves and other special curves. This paper is a study of magnetic curves and this kind of relationships. We give the relationship between β-magnetic curves and Mannheim, Bertrand, involute-evolute curves and we give some geometric properties about them. Then, we study this subject for γ-magnetic curves. Finally, we give an evaluation of what we did.

• 한국생물공학회:학술대회논문집
• /
• 한국생물공학회 2003년도 생물공학의 동향(XIII)
• /
• pp.480-484
• /
• 2003

A stereoselective-hydrolysing enzyme was cloned from Pseudomonas fluorescens KCTC1767 which had high enantiomeric activity toward (S)-ketoprofen ethyl ester. Analyses of typical properties resulted in low thermostability and substrate specificity. A round error-prone PCR and StEP(STaggered Extension Process) was adopted to evolute this character. As a result, the best clone 6-52 was selected which was represented to increased thermostability(40 fold) compared to wild type enzyme in $50^{\circ}C$. Additionally, specific activity toward (S)-ketoprofen ethyl ester and p-nitrophenyl derivatives improved 3 fold and 1.5 fold, respectively. DNA sequence analyses was showed some exchanged amino acid residue that was L120p, 1208v, T249A, D287H and T357A. Which the 120th's leucine substituted for proline was presumed structurally important residue concerning with catalytic activity.

• Kyungpook Mathematical Journal
• /
• 제48권3호
• /
• pp.395-410
• /
• 2008

A one site chemotherapy agent-diffusion model is proposed which accounts for diffusion of chemotherapy agent, normal and cancer cells. It is shown that, by controlling the initial conditions, consequently an initial dose of the chemotherapy agent, the system is guaranteed to evolute towards a target equilibrium state. Or, growth of the normal cells occurs against decay of the cancer cells. Effects of diffusion of chemotherapy-agent and cells are investigated through numerical computations of the concentrations in square and triangular cancer sites.

• 대한치과의사협회지
• /
• 제54권10호
• /
• pp.780-788
• /
• 2016

Dentin bonding systems are unique dental materials which are rapidly evolute and essential materials for bonding of restorative materials to dentin. Now, 4th generation, 5th generation, 6th generation and 7th generation of dentin bonding systems are used in clinic. We investigated the frequency, motivation of choosing dentin bonding systems and satisfaction of them by survey in 2014. 5th generation of dentin bonding systems are mostly used in Korea and young dentist have tendency to choose newly developed dentin bonding systems.

• Tribology and Lubricants
• /
• 제22권2호
• /
• pp.79-86
• /
• 2006

As the gerotor set with ideal profile meshes too tight, the reduction in the size of the rotor is generally adopted for a smooth operation. In this paper, a method of the profile modification for providing clearances was proposed. The meshing properties of the gerotor were analyzed and the non-boundary section of the inner rotor was identified, which denoted that the adjacent chambers were in the same pressure state. Clearances were imposed on the non-boundary section of the inner rotor, and then the profile of that section was modified as a composite curve of arcs. The other sections of the inner rotor were also interpolated as arcs. Thus, the whole profile of the inner rotor was designed as a composite curve of arcs.

• 한국의상디자인학회지
• /
• 제15권4호
• /
• pp.83-99
• /
• 2013

This research is a follow-up study about analysis on the many different customer groups and their various culture trend, which intends to realize diverse values depending on the sense. The purpose of this study was to develop direction forecast for the future fashion industry through consideration about the characteristics of contemporary fashion industry by the change of different customer's culture trend. And also try to find solution to survival strategy of fashion fields able to evolve with customer. Change of the customer's cultural trend draws a shift in policy in the 21st fashion industry as follows : 1) mash-up 2) complexation through decentering and blurring 3) invisible and immaterial value oriented 4) expansion of minor small market. Moreover, this shows sociocultural meaning as follows. First is spread of flexible and horizontal relationship through collaborative consumption and collaboration. Second is concentration on floating and indeterminate chance through dismantling of various different fashion categories. Third is formation of the permanent difference by selection and focus. Last is expansion of understanding about cultural-ecology. Customer cultural trend is 'meme' of cultural gene in fashion field, so it intends to co-evolute with customer by continuous change.

• 대한수학교육학회지:수학교육학연구
• /
• 제20권4호
• /
• pp.511-528
• /
• 2010

기하적 성질을 이해하고 받아들이는 데 있어서 중요한 직관은 학습을 통해서도 형성될 수 있다. 본 연구는 2명의 학생을 대상으로 기호화, 문장화, 증명 과제를 수행하게 하여 기하 증명에서 기호의 중재에 의한 직관의 형성 과정을 살펴본다. 학생들에게 자명하고 당연하게 여겨지는 단정적 직관의 유무에 따라 기호가 어떤 역할을 하는지 살펴보고, 예상적 직관이 형성되지 않은 증명 문제에서 학생들이 기존 지식을 활용하여 증명을 완성하는 과정을 기호의 의미작용에 의해 설명한다. 마지막으로 피타고라스의 정리에 대해 기호의 중재에 의해서 결론적 직관이 형성되는 과정을 살펴본다.