• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2003년도 생물공학의 동향(XIII)
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• pp.586-589
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• 2003

Previously we reported the cloning and sequence analysis of a CFTase gene from Bacillus polymyxa. CFTase was divided into five distinct regions. In order to understand a role of the N-terminal repeat region on the function of CFTase from Bacillus polymyxa MGL21, deletion mutantCFTase ${\Delta}N$ was prepered. Recombinant protein was overproduced in E. coli as inclusion body, solubilized in bufer containing 8M urea, and refolded in the phosphate buffer. The molecular weight of the purified wild type CFTase and CFTase ${\Delta}N$ were 148kDa , 108kDa, respectively.

• BMB Reports
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• 제29권1호
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• pp.63-67
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• 1996

In order to elucidate the molecular mechanism of plasmid incompatibility of broad host-range plasmid R1162, the plasmid-encoded replication protein RepIB was purified and tested for binding to the 20 bp direct repeat (DR) DNA sequence which is reiterated 3 and 1/2 times within the replicative origin of the plasmid. The RepIB protein specifically binds to the DR DNA. Point mutations in the DR which affect expression of plasmid incompatibility also coordinately affect binding. These results indicate that the incompatibility of broad host-range plasmid R1162 is exerted by the DR DNA by titrating the essential replication protein RepIB.

• 한국임상수의학회지
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• 제1권1호
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• pp.33-40
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• 1984

The number of dairy cows diagnosed and treated at Hyup-dong Animal Hospital from July 1983 to June 1984 was amounted to 3,073 heads of Holstein breed and the result of analysis of diseases was as follows : 1. In the topographic diagnostic categories, 41.23% of all cases involved the urogenital system and were observed most prominent. Next were digestive system (22.10%), general and regional (14.55 %), respiratory system (8.20%) and musculoskeletal system (7.06%) in decreasing order. 2. In urogenital system 50.20% of all diagnosis involved metritis and this were most prominent disease. Next were repeat breeder(15.31%), retained placenta (12.79%) and ovary disfunction(9.40 %) in decreasing order. 3. In digestive system 36.82% of all diagnosis involved enteritis and were most prominent. Next were abomasal displacement (29.31%), lumen indigestion (20.32%) and lumen bloat (9.57%) in decreasing order 4. In general and regional diseases, 52.80% of all diagnosis involved ketosis and were most prominent. Next were milk fever (25.50%), downer cow (5.82%) and omphalitis (4.47%) in decreasing order. 5. In respiratory system, 82.54% of all diagnosis involved upper respiratory tract infections and were most prominent. Next were pneumonia (15.87%). 6. In musculoskeletal system, 49.31% of all diagnosis involved foot rot and were most prominent. 7. In milk secreting system, 61.64% of all diagnosis involved mastitis and ere most prominent. Next were stenosis of teat canal (16.35%). 8. Among the individual disease entities, endometritis marked 20.7%, enteritis 8.13%, ketosis 7.68% upper respiratory tract infection 6.77%, repeat bheeder 6.31%, retained placenta 5.27%, abomasal displacement 4.69%, and lumen impaction 4.49%, respectively of total 3,073 cases in decreasing order.

• 한국전자파학회논문지
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• 제22권10호
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• pp.941-950
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• 2011

본 논문에서는 중계기 선택 기법이 적용된 증분 협력 통신의 단-대-단 성능을 분석한다. 일반적인 협력 통신은 1 phase에 송신단(S)에서 전송하는 신호를 수신단(D)이 한 번 수신하고, 2 phase에 중계기(R)로부터 S에서 전송한 신호를 재 전송받게 된다. 이러한 과정을 통해 D는 다이버시티 이득을 얻음으로써 수신 성능이 향상되지만, 두 번에 걸친 전송은 스펙트럼 효율성을 감소시킨다. 하지만 증분형 중계 기법을 적용한 협력 통신에서 D는 1 phase에 수신한 신호만으로 복호에 성공할 수 있다고 판단되면, 두 번째 전송을 생략함으로써 이러한 단점을 보완할 수 있다. 증분형 중계 기법에서 D는 ACK/NACK 메시지를 전송하는 ARQ(Automatic Repeat reQuest) 기법을 이용한다. 본 논문에서는 D가 첫 번째 시간 슬롯에 수신한 신호를 복호할 수 있는지를 판단하기 위해 임계 SNR을 이용한 ARQ 기법과 채널 부호화를 이용한 HARQ(Hybrid Automatic Repeat reQuest) 기법과 같이 두 가지 방법을 고려한 시스템에 참여하는 중계기 배치에 따른 성능을 분석하고, 중계기 배치가 성능에 미치는 영향에 대해 연구한다.

• 대한토목학회논문집
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• 제31권3D호
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• pp.477-487
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• 2011

본 연구는 수정반복매매모형을 활용하여 아파트가격에 영향을 미치는 요인들의 시계열적인 변화를 분석함으로써, 새로운 시설물의 신설이나 환경의 변화가 아파트가격에 미치는 영향력의 차이에 대해 살펴보았다. 지하철 9호선 주변의 아파트단지를 사례대상지로 한 분석결과, 주변 시설까지의 접근성이 아파트가격에 미치는 영향력은 시간에 따라 매우 다른 변화양상을 보이는 것으로 나타났다. 특히, 지하철 9호선이 개통된 이후에 지하철과의 접근성이 아파트가격에 미치는 영향력이 현격히 증가한 반면, 쇼핑시설이나 병원 등은 가격영향력이 상대적으로 감소하였다. 반면, 지하철 이용이 상대적으로 적은 초등학교 접근성은 지하철 개통이후에도 별 변화를 보이지 않았다. 이러한 결과는 새로운 시설의 입지가 주변주택가격 그 자체 뿐만 아니라, 가격에 영향을 미치는 다른 요인들의 영향력의 크기에도 영향을 미침을 시사한다.

• 한국식품위생안전성학회지
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• 제29권4호
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• pp.383-390
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• 2014

The safety of a new natural plant composition (ADP) was assessed on the genotoxicity study and 14-day repeat dose toxicity study. ADP contains a mixed water extract obtained from the mixture of Phellodendron cortex (Phellodendron amurense) and Anemarrhena rhizoma (Anemarrhena asphodeloides), and poses the contractile properties mediated by alpha-adrenoceptor of the prostate and urethra as well as antioxidant and anti-inflammatory properties. In order to evaluate genetic safety, in vivo micronucleus test was performed in ICR mice orally administered with three dose levels of 1250, 2500, 5000 mg/kg body weight, and vehicle and positive control. In the 14 days study, Sprague-Dawley rats were treated with ADP at the dose levels of 500, 1000, 2000 mg/kg once a day, and clinical signs, body weights, hematology, serum biochemistry, necropsy findings and organ weights were monitored and examined. In experimental results, ADP treatment, compared with vehicle control, did not induce the micronucleated erythrocytes from mouse bone marrow. In the 14 days study, any significant and toxicological differences in all measurements of parameters were not observed in ADP treatment groups of animals, compared with vehicle treatment. The No-Observed-Adverse-Effect-Level (NOAEL) of ADP in the 14 days study was determined to be greater than 2000 mg/kg/day in both sexes.

• 산업경영시스템학회지
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• 제43권4호
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• pp.1-14
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• 2020

Recently, M/G/1 priority queues with a finite buffer for high-priority customers and an infinite buffer for low-priority customers have applied to the analysis of communication systems with two heterogeneous traffics : delay-sensitive traffic and loss-sensitive traffic. However, these studies are limited to M/G/1 priority queues with finite and infinite buffers under a work-conserving priority discipline such as the nonpreemptive or preemptive resume priority discipline. In many situations, if a service is preempted, then the preempted service should be completely repeated when the server is available for it. This study extends the previous studies to M/G/1 priority queues with finite and infinite buffers under the preemptive repeat-different and preemptive repeat-identical priority disciplines. We derive the loss probability of high-priority customers and the waiting time distributions of high- and low-priority customers. In order to do this, we utilize the delay cycle analysis of finite-buffer M/G/1/K queues, which has been recently developed for the analysis of M/G/1 priority queues with finite and infinite buffers, and combine it with the analysis of the service time structure of a low-priority customer for the preemptive-repeat and preemptive-identical priority disciplines. We also present numerical examples to explore the impact of the size of the finite buffer and the arrival rates and service distributions of both classes on the system performance for various preemptive priority disciplines.

• 한국전자통신학회논문지
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• 제12권4호
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• pp.569-574
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• 2017

잡음이 존재하는 채널환경에서의 정보전송을 위해서는 정보의 부호화 기술이 필요하다. 오류 검출과 정정에 사용되는 여러 가지 부호화 기술 중 Shannon의 한계에 가장 근접한 부호화 기술이 저밀도 패러티 체크(Low density Parity Check :LDPC) 부호이다. LDPC 부호와 sum-product 알고리즘의 조합에 의하여 얻어지는 복호 특성은 터보 부호, RA(Repeat Accumulate) 부호의 성능에 필적하며, 부호장이 매우 긴 경우에는 이들 성능을 추월한다. 본 논문에서는 영상 정보의 LDPC 부호화와 복호화 기술 원리에 관해 설명하고, Sum-product 알고리듬을 사용하는 LDPC 복호기를 FPGA로 구현한다.

• 한국통신학회논문지
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• 제21권5호
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• pp.1208-1220
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• 1996

본 논문에서는 IEEE 802.11에서 채택한 매체접근제어 프로토콜인 Stop-and-Wait Automatic Repeat reQust(ARQ)방식을 사용하는 Carrier Sence Multiple Access/Collision Avoidance(CSMA/CA) 프로토콜의 성능을 renewal theory를 사용하여 수학적으로 분석하였으며, 컴퓨터 시뮬레이션을 사용하여 분석의 신뢰성을 검증하였다. CSMA/CA 프로토콜의 처리율을 분석하기 위하여 통신망은 유한 가입자로 구성되며, 슬롯화된 채널을 고려하였고, CSMA/CA프로토콜은 1-persistent CSMA와 p-persistent CSMA프로토콜을 혼합한 프로토콜로 모델링하여 CSMA.CA 프로토콜의 처리율 및 패킷지연을 분석하였다. 분석 결과에 의하면, CSMA/CA 방식은 스테이션의 수, Acknowledgement(ACK) 패킷의 길이 및 Distributed coordination function Inter Frame Space(DIFS)의 길이가 커짐에 따라 처리율이 저하되었으며, 패킷 지연이 증가하였다.

• Journal of Communications and Networks
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• 제12권2호
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• pp.174-180
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• 2010

Automatic Repeat reQuest (ARQ) is a very effective technique against transmission error at the medium access control (MAC) layer. An erroneous MAC protocol data unit can be typically retransmitted within a given limit. In order to improve the IP-level performance, which directly affects the user-perceived quality-of-service (QoS), we propose a new truncated ARQ strategy, called MAC service data unit-based ARQ (S-ARQ), where the finite number of opportunities for retransmissions are shared by multiple fragments out of an IP datagram. We describe how SARQ can be implemented in a practical system, and then propose another variant of S-ARQ employing a functionality called early detection of failure. Basically, we evaluate the performance of SARQ in two different manners. First, assuming i.i.d. error process, we analyze both the probability of the delivery failure and the average delay of IP datagram. Then, we assess the performance of S-ARQ via simulation over a 2-state Markov channel.