• Structural Engineering and Mechanics
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• 제54권2호
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• pp.239-256
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• 2015

An adaptive-scale damage detection strategy based on a wavelet finite element model (WFEM) for thin plate structures is established in this study. Equations of motion and corresponding lifting schemes for thin plate structures are derived with the tensor products of cubic Hermite multi-wavelets as the elemental interpolation functions. Sub-element damages are localized by using of the change ratio of modal strain energy. Subsequently, such damages are adaptively quantified by a damage quantification equation deduced from differential equations of plate structure motion. WFEM scales vary spatially and change dynamically according to actual needs. Numerical examples clearly demonstrate that the proposed strategy can progressively locate and quantify plate damages. The strategy can operate efficiently in terms of the degrees-of-freedom in WFEM and sensors in the vibration test.

• 한국수학교육학회지시리즈A:수학교육
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• 제14권1호
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• pp.22-26
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• 1975

In this paper, we define a differential module and study its properties. In section 2, as for propositions, Ive research some properties, directsum, isomorphism of factorization, exact sequence of derived modules. And then as for theorem, I try to present the following statement, if the sequence of homomorphisms of differential modules is exact. Then the sequence of homomorphisms of Z(X) is exact, also the sequence of homomorphisms of Z(X) is exact. According to the theorem, as for Lemma, we consider commutative diagram between exact sequence of Z(X) and exact sequence of Z'(X) . As an immediate consequence of this theorem, we obtain the following result. If M is an arbitrary module and the sequence of homomorphisms of the modules Z(X) is exact, then the sequence of their tensor products with the trivial endomorphism is semi-exact.

• 대한수학회지
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• 제60권6호
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• pp.1137-1169
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• 2023

Let C be a curve and V → C an orthogonal vector bundle of rank r. For r ≤ 6, the structure of V can be described using tensor, symmetric and exterior products of bundles of lower rank, essentially due to the existence of exceptional isomorphisms between Spin(r, ℂ) and other groups for these r. We analyze these structures in detail, and in particular use them to describe moduli spaces of orthogonal bundles. Furthermore, the locus of isotropic vectors in V defines a quadric subfibration Q_V ⊂ ℙV . Using familiar results on quadrics of low dimension, we exhibit isomorphisms between isotropic Quot schemes of V and certain ordinary Quot schemes of line subbundles. In particular, for r ≤ 6 this gives a method for enumerating the isotropic subbundles of maximal degree of a general V , when there are finitely many.

• 한국의류학회지
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• 제44권3호
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• pp.556-571
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• 2020

This study predicts consumer preference for social clothing at work, excluding uniforms using the self-product congruence theory that also establishes a model to predict the preference for recommended products that match the consumer's own image. A total of 490 Korean male office workers participated in this study. Participants' self-image and the product images of 20 apparel items were measured using nine adjective semantic scales (namely elegant, stable, sincere, refined, intense, luxury, bold, conspicuous, and polite). A model was then constructed to predict the consumer preferences using a neural network with Python and TensorFlow. The resulting Predict Preference Model using Product Image (PPMPI) was trained using product image and the preference of each product. Current research confirms that product preference can be predicted by the self-image instead of by entering the product image. The prediction accuracy rate of the PPMPI was over 80%. We used 490 items of test data consisting of self-images to predict the consumer preferences for using the PPMPI. The test of the PPMPI showed that the prediction rate differed depending on product attributes. The prediction rate of work apparel with normative images was over 70% and higher than for other forms of apparel.

• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 2006년 제4회 한국유체공학학술대회 논문집
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• pp.445-448
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• 2006

The effects of surface roughness on a spatially-developing turbulent boundary layer (TBL) were investigated by performing direct numerical simulations of TBLs over rough and smooth walls. The Reynolds number based on the momentum thickness was varied in the range $Re_{\theta}=300{\sim}1400$. The roughness elements used were periodically arranged two-dimensional spanwise rods, and the roughness height was $k=1.5{\theta}_{in}$, which corresponds to $k/{\delta}=0.045{\sim}0.125$. To avoid generating a rough wall inflow, which is prohibitively difficult, a step change from smooth to rough was placed $80{\theta}_{in}$ downstream from the inlet. The spatially-developing characteristics of the rough-wall TBL were examined. Along the streamwise direction, the friction velocity approached a constant value and a self-preserving form of the turbulent stress was obtained. Introduction of the roughness elements affected the turbulent stress not only in the roughness sublayer but also in the outer layer. Despite the roughness-induced increase of the turbulent stress in the outer layer, the roughness had only a relatively small effect on the anisotropic Reynolds stress tensor in the outer layer. Inspection of the triple products of the velocity fluctuations revealed that introducing the roughness elements onto the smooth wall had a marked effect on vertical turbulent transport across the whole TBL. By contrast, good surface similarity in the outer layer was obtained for the third-order moments of the velocity fluctuations.

• Journal of Electrical Engineering and Technology
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• 제8권2호
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• pp.271-281
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• 2013

In order to improve the performance of analysis, it is important to consider the nonlinearity in power system. The Carleman embedding technique (linearization procedure) provides an effective approach in reduction of nonlinear systems. In the approach, a group of differential equations in which the state variables are formed by the original state variables and the vector monomials one can build with products of positive integer powers of them, is constructed. In traditional Carleman linearization technique, the tensor matrix is truncated to form a square matrix, and then regular linear system theory is used to solve the truncated system directly. However, it is found that part of nonlinear information is neglected when truncating the Carleman model. This paper proposes a new approach to solve the problem, by combining the Poincar$\acute{e}$ transformation with the Carleman linearization. Case studies are presented to verify the proposed method. Modal analysis shows that, with traditional Carleman linearization, the calculated contribution factors are not symmetrical, while such problems are avoided in the improved approach.

• 충청수학회지
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• 제13권1호
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• pp.139-144
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• 2000

The generalized noncommutative torus $T_{\rho}^d$ of rank m was defined in [2]. Assume that for the completely irrational noncommutative subtorus $A_{\rho}$ of rank m of $T_{\rho}^d$ there is no integer q > 1 such that $tr(K_0(A_{\rho}))=\frac{1}{q}{\cdot}tr(K_0(A_{\rho^{\prime}}))$ for $A_{\rho^{\prime}}$ a completely irrational noncommutative torus of rank m. All $C^*$-algebras ${\Gamma}({\eta})$ of sections of locally trivial $C^*$-algebra bundles ${\eta}$ over $M=\prod_{i=1}^{e}S^{2k_i}{\times}\prod_{i=1}^{s}S^{2n_i+1}$, $\prod_{i=1}^{s}\mathbb{PR}_{2n_i}$, or $\prod_{i=1}^{s}L_{k_i}(n_i)$ with fibres $T_{\rho}^d{\otimes}M_c(\mathbb{C})$ were constructed in [6, 7, 8]. We prove that ${\Gamma}({\eta}){\otimes}M_{p^{\infty}}$ is isomorphic to $C(M){\otimes}A_{\rho}{\otimes}M_{cd}(\mathbb{C}){\otimes}M_{p^{\infty}}$ if and only if the set of prime factors of cd is a subset of the set of prime factors of p, that $\mathcal{O}_{2u}{\otimes}{\Gamma}({\eta})$ is isomorphic to $\mathcal{O}_{2u}{\otimes}C(M){\otimes}A_{\rho}{\otimes}M_{cd}(\mathbb{C})$ if and only if cd and 2u - 1 are relatively prime, and that $\mathcal{O}_{\infty}{\otimes}{\Gamma}({\eta})$ is not isomorphic to $\mathcal{O}_{\infty}{\otimes}C(M){\otimes}A_{\rho}{\otimes}M_{cd}(\mathbb{C})$ if cd > 1 when no non-trivial matrix algebra can be ${\Gamma}({\eta})$.

• 대한수학회보
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• 제60권6호
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• pp.1555-1566
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• 2023

A Hilbert space operator A ∈ B(H) is a generalised n-projection, denoted A ∈ (G-n-P), if A^*n = A. (G-n-P)-operators A are normal operators with finitely countable spectra σ(A), subsets of the set $\{0\}\,{\cup}\,\{\sqrt[n+1]{1}\}.$ The Aluthge transform à of A ∈ B(H) may be (G - n - P) without A being (G - n - P). For doubly commuting operators A, B ∈ B(H) such that σ(AB) = σ(A)σ(B) and ${\parallel}A{\parallel}\,{\parallel}B{\parallel}\;{\leq}\;{\parallel}{\tilde{AB}}{\parallel},$ ${\tilde{AB}}\;{\in}\;(G\,-\,n\,-\,P)$ if and only if $A\;=\;{\parallel}{\tilde{A}}{\parallel}\,(A_{00}\,{\oplus}\,(A_0\,{\oplus}\,A_u))$ and $B\;=\;{\parallel}{\tilde{B}}{\parallel}\,(B_0\,{\oplus}\,B_u),$ where A₀₀ and B₀, and A₀ ⊕ A_u and B_u, doubly commute, A₀₀B₀ and A₀ are 2 nilpotent, A_u and B_u are unitaries, A^*n_u = A_u and B^*n_u = B_u. Furthermore, a necessary and sufficient condition for the operators αA, βB, αà and ${\beta}{\tilde{B}},\;{\alpha}\,=\,\frac{1}{{\parallel}{\tilde{A}}{\parallel}}$ and ${\beta}\,=\,\frac{1}{{\parallel}{\tilde{B}}{\parallel}},$ to be (G - n - P) is that A and B are spectrally normaloid at 0.

• 한국축산식품학회지
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• 제29권3호
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• pp.364-373
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• 2009

돼지고기 저지방 부위 근육들의 특성에 맞는 이용법을 구명하는데 필요한 기초 자료를 제시하고자 삼원교잡종 돼지도체 10두(거세돼지 5두, 암퇘지 5두)에서 분리한 21개 근육의 육질 특성을 조사하였다. 돼지 저지방 부위를 구성하고 있는 주요 21개 근육의 육질특성을 조사한 결과, subscpularis 근육의 pH가 가장 높았고, gluteus superrificialis 근육이 가장 낮았다(p<0.05). 보수력은 subscpularis 근육이 가장 높았으며(p<0.05), 가열감량은 biceps femoris 근육이 가장 많았고, subscpularis 근육이 적었다(p<0.05). 포장감량은 bluteus superrificialis 근육이 가장 많았고(p<0.05) 콜라겐 함량은 infraspinatus와 gastrocnemius 근육이 가장 많았던 반면에 adductor 근육이 가장 적었다(p<0.05). 전단력은 biceps femoris 근육이 가장 높았고, subscpularis 근육이 가장 낮았다(p<0.05). 단백질 용해성은 pectoralis profundi(fan) 근육이 가장 높았고(p<0.05), 겔 강도는 semitendinosus 근육이 가장 높았다(p<0.05). 육색특성에서 명도 값은 tensor fasciae latae 근육이 가장 높았고(p<0.05), 적색도는 superaspinatus, brachiocephalicus, infraspinatus 근육들이 높았으며, 미오글로빈 함량은 vastus intermedius 근육이 가장 높았고, longissimus dorsi 근육이 가장 낮았다(p<0.05). 관능적 특성 중 연도는 infraspinatus 근육이 가장 연하였던 반면에 biceps femoris 근육이 가장 질겼다(p<0.05). 풍미에서는 pectoralis profundi(fan) 근육이 가장 높은 평가를 받았고, vastus intermedius 근육이 가장 낮은 평가를 받았다(p<0.05). 다즙성에서는 supraspinatus, infraspinatus, semitendinosus, vastus intermedius 근육들이 가장 다즙했던 반면에 longissimus dorsi 근육이 가장 건조했다(p<0.05). 전체기호도는 semitendino년와 infraspinatus 근육이 가장 높은 평가를 받았고, biceps femoris와 longissimus dorsi 근육이 가장 낯은 평가를 받았다(p<0.05). 이상의 결과를 종합하면 돼지 저지방 부위를 구성하는 21개 근육들은 육질적인 측면에서 서로 다른 특성들을 나타내는 것으로 조사되었으며, 이러한 결과는 각 근육들의 특성에 적합한 이용방법 개발에 필요한 기초 자료로 유용할 것으로 사료된다.

• 대한화장품학회지
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• 제34권2호
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• pp.129-135
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• 2008

본 연구에서는 하고초(Prunella vulgaris) 추출물의 항노화 효과에 대하여 알아보고자 하였다. 시험 결과, 하고초 추출물의 콜라겐 생성 촉진 효과는 250 ${\mu}g/mL$ 농도에서 75.7%, MMP-1 생성 억제 효과는 200 ${\mu}g/mL$ 농도에서 90.2%로 나타났고, 엘라스테이즈 활성 억제 효과는 2.0% 농도에서 43.7%로 나타났다. 또한, 하고초 추출물의 항산화 효과 측정을 위한 자유 라티칼 소거 효과 시험 결과 2.0% 농도에서 76.9%의 소거 효과를 나타내었으며, 과산화수소에 의한 세포사멸 억제 효과는 2.0% 농도에서 49.9%로 나타났다. 하고초 추출물의 피부에 대한 영향을 알아보기 위하여 22명(연령분포 : 34세$\sim$48세)의 지원자를 대상으로 실시한 이중 맹검 임상 연구 결과, 하고초 추출물 4.0% 함유 제형을 12주간 도포하였을 때, 대조군과 비교하여 전문가의 육안평가, 모사판을 제작하여 주름의 정도를 분석한 결과 주름 개선에 현저한 효과가 있음을 확인하였다(p<0.05). 이러한 결과를 통해 하고초 추출물은 피부의 탄력과 주름을 효과적으로 개선함으로써, 천연 항노화 소재로 유용하게 이용될 수 있을 것으로 기대된다.