• 제목/요약/키워드: reduction theory

검색결과 805건 처리시간 0.041초

EXISTENCE OF SIX SOLUTIONS OF THE NONLINEAR SUSPENSION BRIDGE EQUATION WITH NONLINEARITY CROSSING THREE EIGENVALUES

  • Jung, Tacksun;Choi, Q.-Heung
    • Korean Journal of Mathematics
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    • 제16권1호
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    • pp.1-24
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    • 2008
  • Let $Lu=u_{tt}+u_{xxxx}$ and E be the complete normed space spanned by the eigenfunctions of L. We reveal the existence of six nontrivial solutions of a nonlinear suspension bridge equation $Lu+bu^+=1+{\epsilon}h(x,t)$ in E when the nonlinearity crosses three eigenvalues. It is shown by the critical point theory induced from the limit relative category of the torus with three holes and finite dimensional reduction method.

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COFINITE PROPER CLASSIFYING SPACES FOR LATTICES IN SEMISIMPLE LIE GROUPS OF ℝ-RANK 1

  • Kang, Hyosang
    • 대한수학회논문집
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    • 제32권3호
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    • pp.745-763
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    • 2017
  • The Borel-Serre partial compactification gives cofinite models for the proper classifying space for arithmetic lattices. Non-arithmetic lattices arise only in semisimple Lie groups of ${\mathbb{R}}$-rank one. The author generalizes the Borel-Serre partial compactification to construct cofinite models for the proper classifying space for lattices in semisimple Lie groups of ${\mathbb{R}}$-rank one by using the reduction theory of Garland and Raghunathan.

DIRICHLET BOUNDARY VALUE PROBLEM FOR A CLASS OF THE ELLIPTIC SYSTEM

  • Jung, Tacksun;Choi, Q-Heung
    • 충청수학회지
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    • 제27권4호
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    • pp.707-720
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    • 2014
  • We get a theorem which shows the existence of at least three solutions for some elliptic system with Dirichlet boundary condition. We obtain this result by using the finite dimensional reduction method which reduces the infinite dimensional problem to the finite dimensional one. We also use the critical point theory on the reduced finite dimensioal subspace.

EXISTENCE OF SIX SOLUTIONS OF THE NONLINEAR HAMILTONIAN SYSTEM

  • Jung, Tack-Sun;Choi, Q-Heung
    • 호남수학학술지
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    • 제30권3호
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    • pp.443-468
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    • 2008
  • We give a theorem of existence of six nontrivial solutions of the nonlinear Hamiltonian system $\.{z}$ = $J(H_z(t,z))$. For the proof of the theorem we use the critical point theory induced from the limit relative category of the torus with three holes and the finite dimensional reduction method.

REDUCTIONS OF IDEALS IN COMMUTATIVE NOETHERIAN SEMI-LOCAL RINGS

  • Song, Yeong-Moo;Kim, Se-Gyeong
    • 대한수학회논문집
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    • 제11권3호
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    • pp.539-546
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    • 1996
  • The purpose of this paper is to show that the Noetherian semi-local property of the underlying ring enables us to develope a setisfactory concep of the theory of reduction of ideals in a commutative Noetherian ring.

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Forest therapy program reduces academic and job-seeking stress among college students

  • Kang, Byung-Hoon;Shin, Won-Sop
    • 인간식물환경학회지
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    • 제23권3호
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    • pp.363-375
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    • 2020
  • Background and objective: Recreation or activities in forest are regarded as therapy. Many forest therapy programs have been developed and assessed in the domestic. This study was conducted to investigate the effect of the forest therapy program on academic and job-seeking stress in college students. Methods: Thirty five subjects were selected as the experimental group and 25 as the control group, and 29 subjects in the experimental group and 11 in the control group participated in the follow-up test to verify the persistence of stress reduction effects. The forest therapy program was carried out once a week for 2 hours each from September 4 to December 4, 2018, adding up to total eight sessions. Results: The experimental group showed statistically significant reduction in both academic stress and job-seeking stress, whereas the control group did not. For the persistence of the forest therapy program, the experimental group did not show a statistically significant difference between the posttest and the follow-up test, and thus the stress reduction effect was maintained. Conclusion: This study proved the reduction of academic and job-seeking stress in forest therapy programs and the persistence of the stress reduction effect of the forest therapy program. The result is consistent with the Stress Recovery Theory (SRT) that shows the stress reduction effect of nature. In addition, it has significance in that it has verified that the program using the forest on campus can reduce stress of most college students.

범밀도함수이론에 기초한 니켈(100) 표면에서의 전기화학적 질소환원반응 메커니즘에 관한 연구 (A Density-Functional Theory Study on Mechanisms of the Electrochemical Nitrogen Reduction Reaction on the Nickel(100) Surface)

  • 김민지;이상헌
    • Korean Chemical Engineering Research
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    • 제61권4호
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    • pp.604-610
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    • 2023
  • 주변 조건에서 N2를 환원하여 NH3를 생성하는 전기 촉매 질소 환원 반응(nitrogen reduction reaction, NRR)은 산업공정에서 에너지 소비를 감소시킬 수 있는 유망한 기술로 주목을 받고 있다. N2를 흡착하고 활성화할 수 있는 촉매 금속 표면 중 많이 사용되는 Ni(100) 표면의 여러 사이트(site)의 흡착 성능을 밀도 함수 이론 계산(density-functional theory)를 기반으로 비교하였다. 또한 안정적인 NRR반응의 경로를 유도하는 N2의 두 가지 흡착 구조를 조사하였고 end-on 구조는 top site에 흡착, distal pathway로 반응이 진행되고 side-on 구조는 bridge site에 흡착되며 enzymatic pathway로 반응이 진행되었다. 마지막으로 구조 별 가장 안정한 메커니즘의 깁스 자유에너지를 구하여 반응의 경향성을 알아봄으로써 NRR 반응의 금속 촉매 표면 흡착에 대한 연구에 도움이 될 수 있을 것이다.

ON THE p-PRIMARY PART OF TATE-SHAFAREVICH GROUP OF ELLIPTIC CURVES OVER ℚ WHEN p IS SUPERSINGULAR

  • Kim, Dohyeong
    • 대한수학회보
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    • 제50권2호
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    • pp.407-416
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    • 2013
  • Let E be an elliptic curve over $\mathbb{Q}$ and $p$ be a prime of good supersingular reduction for E. Although the Iwasawa theory of E over the cyclotomic ${\mathbb{Z}}_p$-extension of $\mathbb{Q}$ is well known to be fundamentally different from the case of good ordinary reduction at p, we are able to combine the method of our earlier paper with the theory of Kobayashi [5] and Pollack [8], to give an explicit upper bound for the number of copies of ${\mathbb{Q}}_p/{\mathbb{Z}}_p$ occurring in the $p$-primary part of the Tate-Shafarevich group of E over $\mathbb{Q}$.

도시 소유역 유효불투수율의 민감도 분석 (Sensitivity analysis of effective imperviousness estimation for small urban watersheds)

  • 김대근;고영찬
    • 상하수도학회지
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    • 제23권2호
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    • pp.181-187
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    • 2009
  • In this study, a runoff hydrograph and runoff volume were calculated by using the kinetic wave theory for small urban watersheds based on the concept of low impact development(LID), and the effective imperviousness was estimated based on these calculations. The degree of sensitivity of the effective imperviousness of small watersheds to the impervious to pervious area ratio, infiltration capability, watershed slope, roughness coefficient and surface storage depth was then analyzed. From this analysis, the following conclusions were obtained: The effective imperviousness and paved area reduction factor decreased as the infiltration capability of pervious area increased. As the slope of watersheds becomes sharper, the effective imperviousness and the paved area reduction factor display an increasing trend. As the roughness coefficient of impervious areas increases, the effective imperviousness and the paved area reduction factor tend to increase. As the storage depth increases, the effective imperviousness and the paved area reduction factor show an upward trend, but the increase is minimal. Under the conditions of this study, it was found that the effective imperviousness is most sensitive to watershed slope, followed by infiltration capability and roughness coefficient, which affect the sensitivity of the effective imperviousness at a similar level, and the storage depth was found to have little influence on the effective imperviousness.

플랩 블레이드를 이용한 조류 터빈의 부하 저감에 대한 연구 (Study on Load Reduction of a Tidal Steam Turbine Using a Flapped Blade)

  • 정다솜;고진환
    • Ocean and Polar Research
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    • 제42권4호
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    • pp.293-301
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    • 2020
  • Blades of tidal stream turbines have to sustain many different loads during operation in the underwater environment, so securing their structural safety is a key issue. In this study, we focused on periodic loads due to wave orbital motion and propose a load reduction method with a blade design. The flap of an airplane wing is a well-known structure designed to increase lift, and it can also change the load distribution on the wing through deflection. For this reason, we adopted a passive flap structure for the load reduction and investigated its effectiveness by an analytical method based on the blade element moment theory. Flap torsional stiffness required for the design of the passive flap can be obtained by calculating the flap moment based on the analytic method. Comparison between a flapped and a fixed blade showed the effect of the flap on load reduction in a high amplitude wave condition.