• Title, Summary, Keyword: TRC

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Effect of redox potential on the production of succinic acid by metabolically engineered Escherichia coli

  • Hong, Sun-Ho;Lee, Sang-Yeop
    • 한국생물공학회:학술대회논문집
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    • pp.665-668
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    • 2000
  • Recombinant Escherichia coli NZN111 ($F-{\Delta}pfl::Cam$ ldhA::Kan) harboring pTrcML, a plasmid containing the E. coli malic enzyme gene, produced considerable amount of malic acid along with the desired product succinic acid. This seemed to be due to the unmatched redox states between glucose and succinic acid. Therefore, a more reduced carbon substrate sorbitol was examined for the possibility of matching the potential during succinic acid production. When NZN111 (pTrcML) was cultured in LB medium containing 20 g/L sorbitol under $CO_2$ atmosphere, 10 g/L of succinic acid was produced. The apparent yield of succinic acid was 1.1 g succinic acid per g sorbitol, which is 85% of the maximum theoretical yield.

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Query Expansion Using Thesaurus for Korean to Chinese Cross- Language Text Retrieval (한.중 교차언어 검색에서 시소러스를 이용한 질의 확장)

  • Jin, Feng;Kang, In-Su;Lee, Jong-Hyeok
    • Proceedings of the Korean Information Science Society Conference
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    • pp.538-540
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    • 2003
  • 본 논문은 한.중 교차언어 검색을 위한 효과적인 질의 확장에 대해 기술하고 있다. 한.중 교차언어 검색은 한국어 질의로 중국어 문서를 검색하는 것이고 본 논문에서는 대역어 사전을 이용하여 한국어 질의를 중국어 질의로 변환하는 방식을 사용한다. 질의 확장을 위한 방법으로 중국어 시소러스인“동의사사림”을 사용하였다. 그리고 동의어들과 주변 단어간의 상호 정보를 비교함으로서 재현률과 정확률을 높였다. 실험을 통하여 검증한 결과 사전만 사용하여 변환하는 방법에 비하여 검색 성능이 향상되었다.

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Construction of Recombinant Xanthomonas campestris Strain Producing Insecticidal Protein of Bacillus thuringiensis

  • Shin, Byung-Sik;Koo, Bon-Tag;Choi, Soo-Keun;Park, Seung-Hwan
    • Journal of Microbiology and Biotechnology
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    • v.4 no.4
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    • pp.285-289
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    • 1994
  • An insecticidal crystal protein gene, cryIA(c), from Bacillus thuringiensis HD-73 was integrated into the chromosome of a xanthan-producing bacterium, Xanthomonas campestris XP92. The cryIA(c) gene expression cassette was constructed that placed the gene between the trc promoter and rrnB transcriptional terminator. The $lacl^q$ gene was also included to prevent the expression of cryIA(c) gene in X campestris cells. Southem blot analysis confirmed the integration of the cryIA(c) gene expression cassette in chromosome of X campestris XP92 transconjugant. Expression of the insecticidal crystal protein was confirmed by Western blot analysis and bioassay against the larvae of Hyphantria cunea (Lepidoptera: Arctiidae) and Plutella xylostella (Lepidoptera:Plutellidae).

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An Integrated Game Theoretical Approach for Primary and Secondary Users Spectrum Sharing in Cognitive Radio Networks

  • Kim, Jong-Gyu;Nguyen, Khanh-Huy;Lee, Jung-Tae;Hwang, Won-Joo
    • Journal of Korea Multimedia Society
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    • v.14 no.12
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    • pp.1549-1558
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    • 2011
  • In this paper, we address the problem of bandwidth sharing among multiple primary users and multiple secondary users in a cognitive radio network. In cognitive radio networks, effective spectrum assignment for primary and secondary users is a challenge due to the available broad range of radio frequency spectrum as well as the requisition of harmonious coexistence of both users. To handle this problem, firstly, Bertrand game model is used to analyze a spectrum pricing in which multiple primary users emulate with each other to acquire maximal profit. After that, we employ Cournot game to model the spectrum sharing of secondary users to obtain optimal profit for each user also. Simulation results show that our scheme obtains optimal solution at Nash equilibrium.

Fabrication of AA4343 Alloys by Twin Roll Casting and their Properties (쌍롤 박판주조법에 의한 AA4343 합금의 제조 및 특성)

  • Euh, Kwang-Jun;Kim, Min-Gyun;Baek, Eun-Ji;Kim, Hyoung-Wook
    • Proceedings of the KAIS Fall Conference
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    • pp.646-648
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    • 2011
  • 본 논문에서는 쌍롤 박판주조(Twin Roll Casting, TRC)법을 이용하여 AA4343 합금을 제작하였다. 주조시 롤 간격을 조절하여 냉각속도를 달리하였으며 인고트 주조(Ingot Casting, IC)법을 이용하여 제조된 합금과의 미세조직학적 차이와 이에 따른 물성 변화를 고찰하였다. TRC 및 IC로 제조된 합금을 냉간압연하였으며 압연 건전성을 평가하였다. 한편, 냉각속도별로 상이한 미세조직을 구현할 수 있는 스텝몰드(Step Mold Casting, SMC)법을 이용하여 제조된 합금의 냉각속도에 따른 미세조직 및 경도 차이를 조사하여 상대 비교하였다. 냉각속도가 빠를수록 주조 셀조직의 크기 및 공정 Si 입자의 크기가 감소하였으며 이로 인하여 경도가 증가되는 효과를 나타내었다. 주조시 생성된 공정 Si 입자의 크기는 압연에 의하여 그 크기의 변화가 거의 없었으며 열분석 결과 액상선 온도의 변화가 일부 발생하나 큰 차이가 없었다.

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Mobility Management Scheme Based On Identifier/Locator Separation in Mobile IP Environment for Future Internet

  • Huynh, Thong;Hwang, Won-Joo
    • Journal of Korea Multimedia Society
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    • v.15 no.12
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    • pp.1492-1498
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    • 2012
  • One of the major issues in current internet architecture is that it was not designed to support the user mobility. In order to overcome this restriction, in this paper, we propose an identifier/locator separation architecture which contain the overlay mapping system to store the identifier-to-locator mapping record. In addition, we design the mobility management scheme base on Identifier/Locator separation above for Furture Internet architecture. We then devise the analysis model to evaluate the signaling cost of our scheme. By conducting the simulation. we show that our scheme can operate with lower signaling cost than other schemes.

Energy-Efficient Base Station Operation in Heterogeneous Cellular Networks

  • Nguyen, Hoang-Hiep;Hwang, Won-Joo
    • Journal of Korea Multimedia Society
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    • v.15 no.12
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    • pp.1456-1463
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    • 2012
  • In this paper, we study the ON/OFF control policy of base stations in two-tier heterogeneous cellular networks to minimize the total power consumption of the system. Using heterogeneous cellular networks is a potential approach of providing higher throughput and coverage compared to conventional networks with only macrocell deployment, but in fact heterogeneous cellular networks often operates regardless of total power consumption, which is a very important issue of modern cellular networks. We propose a policy that controls the activation/deactivation of base stations in heterogeneous cellular networks to minimize total power consumption. Under this policy, the total power consumed can be significantly reduced when the traffic is low while the QoS requirement is satisfied.

Facilitating Data Source Movement with Time-Division Access in Content-Centric Networking

  • Priyono, Olivica;Kong, In-Yeup;Hwang, Won-Joo
    • Journal of Korea Multimedia Society
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    • v.17 no.4
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    • pp.433-440
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    • 2014
  • Wireless communication offers the flexibility to the node movement at the spatial dimension more than the wire communication not only in IP architecture but also in Content-Centric Networking. Although it gives such advantage, the intra-domain movement of a node especially the data source node affects the communication to the access point node which in the end affects the acceptance ratio of the client node that requests the data packets from the data source node. In this paper, we use time-division access method to maintain the acceptance ratio of the client node as the effect of the intra-domain data source node movement in Content-Centric Networking. The simulation result shows that the acceptance ratio of the client node can be maintained using the time-division access method as long as the interval access time is less than the coherence time.