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Generalized Weyl's Theorem for Some Classes of Operators

  • Mecheri, Salah
    • Kyungpook Mathematical Journal
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    • 제46권4호
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    • pp.553-563
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    • 2006
  • Let A be a bounded linear operator acting on a Hilbert space H. The B-Weyl spectrum of A is the set ${\sigma}_{B{\omega}}(A)$ of all ${\lambda}{\in}\mathbb{C}$ such that $A-{\lambda}I$ is not a B-Fredholm operator of index 0. Let E(A) be the set of all isolated eigenvalues of A. Recently in [6] Berkani showed that if A is a hyponormal operator, then A satisfies generalized Weyl's theorem ${\sigma}_{B{\omega}}(A)={\sigma}(A)$\E(A), and the B-Weyl spectrum ${\sigma}_{B{\omega}}(A)$ of A satisfies the spectral mapping theorem. In [51], H. Weyl proved that weyl's theorem holds for hermitian operators. Weyl's theorem has been extended from hermitian operators to hyponormal and Toeplitz operators [12], and to several classes of operators including semi-normal operators ([9], [10]). Recently W. Y. Lee [35] showed that Weyl's theorem holds for algebraically hyponormal operators. R. Curto and Y. M. Han [14] have extended Lee's results to algebraically paranormal operators. In [19] the authors showed that Weyl's theorem holds for algebraically p-hyponormal operators. As Berkani has shown in [5], if the generalized Weyl's theorem holds for A, then so does Weyl's theorem. In this paper all the above results are generalized by proving that generalizedWeyl's theorem holds for the case where A is an algebraically ($p,\;k$)-quasihyponormal or an algebarically paranormal operator which includes all the above mentioned operators.

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국방 M&S VV&A 적용 및 발전방안 연구(시험평가를 위한 M&S를 중심으로) (A Study on Application and Promotion of DM&S VV&A(Focused on M&S for Test and Evaluation))

  • 김형현;이창희;조내현
    • 한국시뮬레이션학회논문지
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    • 제18권4호
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    • pp.157-164
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    • 2009
  • 1980년대 이후로 컴퓨터 산업의 급격한 발달과 함께 M&S 사용도 급속히 증가하고 있다. M&S를 사용하면 개발비용, 개발 기간 등을 단축시킬 수 있고, 현실적으로 시험이 불가능한 경우에도 M&S를 통하여 시험결과를 얻을 수 있다. 그러나 여기에는 중요한 전제조건이 있다. 그것은 개발 중에 있거나 사용 중에 있는 M&S를 믿을 수 있는냐? 하는 것이다. 본 논문은 VV&A 핵심개념과 국방분야 M&S 적용 및 VV&A 사례 등을 고찰하고, VV&A 적용 및 발전 방안을 제시하고자 한다.

ON THE MODIFICATION OF FINITE FIELD BASED S-BOX

  • Kim, Jun Kyo
    • East Asian mathematical journal
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    • 제37권1호
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    • pp.1-7
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    • 2021
  • In modern block ciphers, S-box plays a very important role in the secrets of symmetric encryption algorithms. Many popular block ciphers have adopted various S-Boxes to design better S-Boxes. Among the researches, Jin et al. proposed a simple scheme to create a new S-box from Rijndael S-box. Only one of the new S-boxes for 29 is a bijection with a better algebraic representation than the original. Therefore, they asked a few questions. In this paper, we answer the following question : When the resulting S-box is bijection?

SOME RESULTS ON S-ACCR PAIRS

  • Hamed, Ahmed;Malek, Achraf
    • 대한수학회논문집
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    • 제37권2호
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    • pp.337-345
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    • 2022
  • Let R ⊆ T be an extension of a commutative ring and S ⊆ R a multiplicative subset. We say that (R, T) is an S-accr (a commutative ring R is said to be S-accr if every ascending chain of residuals of the form (I : B) ⊆ (I : B2) ⊆ (I : B3) ⊆ ⋯ is S-stationary, where I is an ideal of R and B is a finitely generated ideal of R) pair if every ring A with R ⊆ A ⊆ T satisfies S-accr. Using this concept, we give an S-version of several different known results.

어류 기생성 선충 Anisakis simplex sensu stricto와 Anisakis pegreffii 유충의 excretory-secretory products 및 somatic extracts의 가수분해효소 활성 비교 (A comparison of the hydrolase activities of excretory-secretory products and somatic extracts from fish parasitic nematodes, Anisakis simplex sensu stricto and Anisakis pegreffii larvae)

  • 전찬혁;위성;김정호
    • 한국어병학회지
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    • 제27권1호
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    • pp.25-33
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    • 2014
  • Anisakis simplex sensu stricto와 A. pegreffii의 3기 유충과 4기 유충에서 얻은 excretory-secretory (ES) products 및 somatic extracts의 가수분해효소 활성을 API ZYM kit를 이용하여 비교하였다. Esterase 그룹의 가수분해효소 중 acid phosphatase는 A. simplex (s.s.)와 A. pegreffii 모두에서 높은 활성을 나타냈으며, esterase (C 4)의 경우 somatic extracts에서만 가수분해효소 활성이 나타났는데 A. simplex (s.s.)가 A. pegreffii와 비교하여 3기와 4기 유충 모두에서 2배 가량 높은 활성을 나타냈다. alkaline phosphatase, acid phosphatase 그리고 naphthol-AS-BI-phosphohydrolase의 경우 A. simplex (s.s.)와 A. pegreffii 모두 3기 유충보다 4기 유충에서 더 높은 가수분해효소 활성이 확인되었다. Aminopeptidase 그룹의 가수분해효소 활성은 leucine arylamidase에서 관찰되었는데, somatic extracts의 경우 A. pegreffii 보다 A. simplex (s.s.)에서 가수분해 효소 활성이 두 배 가량 높게 확인되었으며, 대부분의 다른 효소들에서는 활성이 거의 나타나지 않았다. Glycosidase 그룹의 가수분해효소 활성은 N-acetyl-${\beta}$-glucosaminidase, ${\alpha}$-mannosidase 그리고 ${\alpha}$-fucosidase에서 확인되었는데, A. simplex (s.s.) 보다 A. pegreffii에서 높은 가수분해효소 활성을 확인할 수 있었으며, 대부분 4기 유충보다 3기 유충에서 더 높은 가수분해효소 활성이 확인되었다. 이러한 아니사키스속 선충의 종과 유충단계에 따른 가수분해 효소의 활성 차이는 선충의 성장, 탈피, 소화, 섭이 등의 대사과정의 차이에 기인한 것으로 생각된다.

EXTENSIONS OF NAGATA'S THEOREM

  • Hamed, Ahmed
    • 대한수학회지
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    • 제55권4호
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    • pp.797-808
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    • 2018
  • In [1], the authors generalize the concept of the class group of an integral domain $D(Cl_t(D))$ by introducing the notion of the S-class group of an integral domain where S is a multiplicative subset of D. The S-class group of D, $S-Cl_t(D)$, is the group of fractional t-invertible t-ideals of D under the t-multiplication modulo its subgroup of S-principal t-invertible t-ideals of D. In this paper we study when $S-Cl_t(D){\simeq}S-Cl_t(D_T)$, where T is a multiplicative subset generated by prime elements of D. We show that if D is a Mori domain, T a multiplicative subset generated by prime elements of D and S a multiplicative subset of D, then the natural homomorphism $S-Cl_t(D){\rightarrow}S-Cl_t(D_T)$ is an isomorphism. In particular, we give an S-version of Nagata's Theorem [13]: Let D be a Krull domain, T a multiplicative subset generated by prime elements of D and S another multiplicative subset of D. If $D_T$ is an S-factorial domain, then D is an S-factorial domain.

Platinum(Ⅱ) Complexes of 2,2$^\prime$-Diaminobinaphthyl

  • 전무진;최성락
    • Bulletin of the Korean Chemical Society
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    • 제6권4호
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    • pp.214-217
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    • 1985
  • Platinum(II) complexes of R-2,2'-diaminobinaphthyl (R-dabn), [Pt(R-dabn)(H2O)2]Cl2, [Pt(R-dabn)(R-Pn)]Cl2, [Pt(R-dabn)(R-bn)]Cl2, and platinum(II) complexes of S-2,2'-diaminobinaphthyl (S-dabn), [Pt(S-dabn)(H2O)2]Cl2, [Pt(S-dabn)(S-Pn)]Cl2, and [(Pt(S-dabn)(S-bn)]Cl2 have been prepared. (R-Pn and S-Pn are, respectively R- and S isomer of 2,3-diaminobutane). R-Pn and S-bn are, respectively R and S isomer of 2,3-diaminopropane). In the vicinity of the B-absorption band region of dabn, the circular dichroism spectra of platinum(Ⅱ) complexes of R-dabn series show a positive B-band followed by a negative higher energy A-band, which is generally understood as the splitting pattern for a ${\lambda}$ conformation, while the circular dichroism spectra of platinum(Ⅱ) complexes of S-dabn series show a negative B-band followed by a positive higher energy A-band in the long-axis polarized absorption region as expected for a $\delta$ conformation.

심실중격결손, 심방중격결손, 폐동맥협착과 우심증을 동반한 완전대혈관전위증의 치험 (A successful Mustard operation for complete transposition of the great arteries combined with VSD, ASD, dextrocardia and PS: a report of one case)

  • 조중구
    • Journal of Chest Surgery
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    • 제15권3호
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    • pp.346-354
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    • 1982
  • A Complete transposition of the great arteries combined with V.S.D, A.S.D, dextrocardia, and P.S is a rare congenital anomaly. The patient was a 10 year-old female whose complaints were frequent URI, exertional dyspnea, and cyanosis at rest since birth. Cheat X-ray films showed Dextrocardia ; situs inversus, moderate cardiomegaly, and Characteristic egg-shape heart shadow. E.K.G, Echocardiography, Cardiac Catheterization, and Angio-Cardiography were performed. Open heart Surgery was done under diagnosis of d-TGA, Dextrocardia, V.S.D, A.S.D, and P.S. At the time of Operation, Dextroeardia, T.G.A, Secndum type A.S.D, A.S.D, and P.S. At the time of Operation, Dextroeardia, T.G.A, Secndum type A.S.D. ($2.0{\times}2.0cm$. in diameter), V.S.D. type II ($1.5cm{\times}1.5cm$ in diameter), and pulmonary valvular stenosis were noted. Mustard operation using pericardial Baffle in the atrium for T.G.A. was perforsned. Teflon patch graft for closure of V.S.D. through tricuspid orifice and pulmonary Valvulotomy through pulmonary arteriotomy were performed. The post-op, low cardiac output Syndrome and dysrhythmicawere developed till Postoperative day #7, so that was controlled by inotropic and antiarrhythmic agents. After that, patient's conditions were Uneventful.

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박물관의 전시소통매체가 방문객의 만족도와 재방문에 미치는 영향에 대한 연구 (Subject: A Study on the Influence of Exhibition Communication Media on a Visitor's Satisfaction and Re-visit)

  • 김형준
    • 대한안전경영과학회지
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    • 제17권4호
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    • pp.321-333
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    • 2015
  • This study empirically analyzed the influence of media on a visitor's satisfaction and re-visit by setting up 5 sorts of exhibition media as text, docent, virtual museum, website and Smartphone App based on practical exchange and communication between a visitor and an exhibition provider. The research results are as follows: First, all these 5 sorts of media suggested by this study were found to be able to have an influence on a visitor's satisfaction and re-visit. Second, it was found that the factors preferentially affecting a visitor's satisfaction and re-visit were 'Docent' and 'Website' factors. Accordingly, it is judged that it's necessary to more preferentially consider 'Docent' and 'Website' factors than the other factors in order to increase a visitor's satisfaction and re-visit. Third, it's possible to interpret that the bigger a visitor's satisfaction, the higher a visitor's intention to re-visit through the verification that a visitor's satisfaction will have a significant influence on a visitor's re-visit. The implication of this study lies in the fact that this study attempted at an integrated approach by analyzing the relative size of the influence through across-the-board suggestion of influential factors on a museum visitor's satisfaction and re-visit.

우연한 패권거부 - 미국의 세계리더십 거부와 중국의 틈새공략 - (The Accidental Denial of a Hegemonic Power's Role - The Reluctance of the U.S's Role as a World Leader and China's Target of a Niche Market -)

  • 반길주
    • Strategy21
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    • 통권42호
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    • pp.224-257
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    • 2017
  • As the Trump administration withdraws the Paris Climate Agreement and shows its antipathy toward free trade, the U.S.'s soft power is most likely to weaken and its behaviors could be perceived as acts to surrender the U.S. hegemonic leadership in the world stage. Hegemonic stability theory notes that the existence of a hegemonic power contributes to international stability in the sense that it provides international public goods. A lack of the U.S's leadership in international politics, however, could be recognized as its denial of a hegemonic status. Is it intentional or accidental? The U.S's denial of hegemonic roles is the byproduct of the Trump administration's "American First" policy, not the showcase of its intention to transit hegemony to others. What is noteworthy is that China targets a niche market of hegemony as the U.S. denies its roles as the international leader. Put it another way, China attempts to ride hegemony for free when the U.S. denies its hegemonic roles accidentally. Faced with a niche market of hegemony, China has begun to accelerate its national strategy to make "Chinese Dream" come true. To that end, China promised again to keep the Paris Climate Agreement and attempts to play more active its roles in Shanghai Cooperation Organization(SCO), Asia Infra Investment Bank(AIIB), and "One Belt, One Road". Despite all these efforts, the U.S. is most likely to withdraw its denial of hegemony any time soon. The U.S's resumption of Freedom of Navigation Operations(FONOPs) could be a precursor of the return to a hegemonic power's willingness. In this vein, it is noteworthy that the South China Sea serves as a quasi-war zone for hegemonic conflict.