• 제목/요약/키워드: NHC

검색결과 37건 처리시간 0.024초

ATM망에서 P-NNI 라우팅을 이용한 개선된 NHRP의 성능평가 (Performance Evaluation of Improved NHRP using P-NNI Routing over ATM Network)

  • 조성기;변태영
    • 한국정보과학회:학술대회논문집
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    • 한국정보과학회 2001년도 가을 학술발표논문집 Vol.28 No.2 (3)
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    • pp.820-822
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    • 2001
  • 본 논문에서는 다수의 LIS들로 구성된 ATM 망에서 특정 IP를 가진 ATM 호스트의 ATM 주소를 해석 하는 NHRP의 주소 해석 시간을 줄이고자, P-NNI 라우팅에 의한 short-cut 경로를 이용한 개선된 NHRP를 제안하였다. 제안된 방식에서는 주소해석을 실제로 담당한 NHS가 NHC에게 NHRP Reply 메시지를 전달 할 경우 short-cut경로를 설정하여 전달함으로써 기존의 NHRP에 비해 주소해석시간을 줄이고 주소해석의 신뢰성을 높일수 있음을 시뮬레이션을 통해 보였다.

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Compression Method for IPSec over 6LoWPAN

  • Wang, Huqing;Sun, Zhixin
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • 제12권4호
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    • pp.1819-1831
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    • 2018
  • This paper focuses on a header compression method for the Authentication Header (AH) and Encapsulation Security Payload (ESP) for application to 6LoWPAN. Based on the context, an extendible compression method is developed by analysing each field of the AH and ESP. The method is carried out by resetting the AH and ESP header compression formats, adding a MOD field, and setting different working modes. Authentication, encryption, and a mixture of certification and encryption are provided as flexible options. In addition, the value of the original IPv6 extensible header ID (EID) field can be retained, while the number of occupied NHC_ID values can be decreased for future extendibility. The experimental results show the feasibility and validity of the current compression method. By comparison with other solutions, the new mechanism is demonstrated to be advantageous in terms of compression ratio, flexibility and extendibility.

대칭적 Triazine 유도체들에 의한 중성 유제층의 경막시험에 관한 연구 (Studies on the Hardening Test of Neutral Emulsion Layers by Derivatives of Symmetrical Triazine)

  • 김영찬
    • 한국응용과학기술학회지
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    • 제24권2호
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    • pp.205-210
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    • 2007
  • In this paper, we describe a study on the relationship between neutral emulsion manufacture and hardening test of films. The hardeners were prepared by condensation of equimolar amounts of trichlorotriazine with benzene- or naphthalene-based amino or oxy acids at 0 to $5^{\circ}C$ and at pH 7, and used as hardening agents for gelatin. The hardening test of neutral emulsion layers was studied at pH 7.0. For example I(R=ONa) had strong hardening properties, I substituted with an aminobenzosulfonate moiety $(R=NHC_6H_4-p-SO_3Me$ where Me = K, Na) was a much weaker gelatin hardener, and when substituted with amino- or oxynaphthalene derivative (II, III) did not harden gelatin at all. Compound with 2 dichlorotriazine groups as IV exhibited hardening properties. The hardener can be used in neutral emulsion layer of film and showed good hardening effect.

대칭적 Triazine 유도체들에 의한 알칼리성 Magenta 유제층의 경막시험에 관한 연구 (Studies on the Hardening Test of Alkaline Magenta Emulsion Layers by Derivatives of Symmetrical Triazine)

  • 김영찬
    • 정보학연구
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    • 제10권2호
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    • pp.29-35
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    • 2007
  • In this paper, we describe a study on the relationship between alkaline magenta emulsion manufacture and hardening test of films. The hardeners were prepared by condensation of equimolar amounts of trichlorotriazine with benzene-or naphthalene-based amino or oxy acids at 0 to $5^{\circ}C$ and at pH 7, and used as hardening agents for gelatin. The hardening test of alkaline magenta emulsion was studied at pH 8.5. For example I(R=ONa) had strong hardening properties, I substituted with an aminobenzosulfonate moiety (R=NHC6H4-p-SO3Me where Me = K, Na) was a much weaker gelatin hardener, and when substituted with amino- or oxynaphthalene derivative (II, III) did not harden gelatin at all. Compound with 2 dichlorotriazine groups as IV exhibited hardening properties. The hardener can be used in alkaline magenta emulsion layer of film and showed good hardening effect.

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Novel Synthesis of 3-Phenyl-chromen-4-ones Using N-Heterocyclic Carbene as Organocatalyst: An Efficient Domino Catalysis Type Approach

  • Mishra, Priya;Singh, Sarita;Ankit, Preyas;Fatma, Shahin;Singh, Divya;Singh, Jagdamba
    • Bulletin of the Korean Chemical Society
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    • 제34권4호
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    • pp.1070-1076
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    • 2013
  • Herein is reported a simple and efficient synthesis of isoflavones starting from various substituted phenacyl bromides and salicylaldehydes in presence of NHC. The mechanism involved domino catalysis type approach with consumption and regeneration of catalyst in two catalytic cycles. This method proved to be very lucrative and gives very good yield. The method described here represents an environmentally benign alternative to classical approach.

Synthesis of Terphenyls and Quaterphenyls via the Nickel N-Heterocyclic Carbene-Catalyzed Cross-Coupling of Neopentyl Arenesulfonates with Aryl Grignard Reagents

  • Jo, Hyun-Jong;Kim, Chul-Bae;Ryoo, Tae-Yong;Ahn, Bo-Kyoung;Park, Kwang-Yong
    • Bulletin of the Korean Chemical Society
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    • 제31권12호
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    • pp.3749-3754
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    • 2010
  • Various terphenyl and quaterphenyl derivatives were prepared by the Ni-NHC catalyzed cross coupling of the corresponding biphenyl- and terphenyl-sulfonates with arylmagnesium bromides. The reactions proceeded rapidly via a nucleophilic aromatic substitution of the alkoxysulfonyl moieties by the aryl nucleophiles to afford high yields within just 1.5 h at room temperature in spite of the low reactivity of the sulfur electrophiles.

대칭적 Triazine 유도체들에 대한 젤라틴 유제층의 경막 시험에 관한 연구 (Studies on the Hardening Test of Gelatin Emulsion Layers by Derivatives of Symmetrical Triazine)

  • 김영찬
    • 정보학연구
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    • 제9권1호
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    • pp.1-7
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    • 2006
  • In this paper, we describe a study on the relationship between photographic emulsion manufacture and hardening test of films. The hardeners were prepared by condensation of equimolar amounts of trichlorotriazine with benzene- or naphthalene-based amino or oxy acids at 0 to 5$^{\circ}C$ and at pH 7, and used as hardening agents for gelatin. The hardening test of photographic emulsion was studied at pH 5.5. For example I(R=ONa) had strong hardening properties, I substituted with an aminobenzosulfonate moiety (R=$NHC_6H_4-p-SO_3Me$ where Me = K, Na) was a much weaker gelatin hardener, and when substituted with amino- or oxynaphthalene derivative (II, III) did not harden gelatin at all. Compound with 2 dichlorotriazine groups as IV exhibited strong hardening properties. The hardener can be used in photographic emulsion of film and showed very good hardening effect.

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Nucleophilic Substitution Reactions of α-Bromoacetanilides with Benzylamines

  • Adhikary, Keshab Kumar;Kim, Chan-Kyung;Lee, Bon-Su;Lee, Hai-Whang
    • Bulletin of the Korean Chemical Society
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    • 제29권1호
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    • pp.191-196
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    • 2008
  • Kinetic studies of the reactions of a-bromoacetanilides [YC6H4NHC(=O)CH2Br] with substituted benzylamines (XC6H4CH2NH2) have been carried out in dimethyl sulfoxide at 35.0 oC. The Hammett plots for substituent (Y) variations in the substrate (log kN vs. sY) are biphasic concave upwards/downwards with breaks at Y = 4-Cl (sY = 0.23). The Hammett coefficients rY and the cross-interaction constant rXY (= +0.16) are positive for sY 0.23, while the rY values are positive/negative [rY > 0 for X = (4-MeO and 4-Me) and rY < 0 for X = (H, 4-Cl and 3-Cl)] and the rXY (= -1.51) value is negative for sY ³ 0.23. Based on these and other results, the benzylaminolyses of a-bromoacetanilides are proposed to proceed through rate-limiting expulsion of the bromide leaving group from a zwitterionic tetrahedral intermediate, T, with a bridged transition state for s Y 0.23, while the reaction proceeds through concerted mechanism with an enolate-like TS in which the nucleophile attacks the a-carbon for s Y ³ 0.23.