• Journal of Microbiology and Biotechnology
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• 제21권6호
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• pp.652-658
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• 2011

The growth kinetics of Streptomyces noursei NRRL 5126 was investigated under different aeration and agitation combinations in a 5.0 l stirred tank fermenter. Poly-${\varepsilon}$-lysine biosynthesis, cell mass formation, and glycerol utilization rates were affected markedly by both aeration and agitation. An agitation speed of 300 rpm and aeration rate at 2.0 vvm supported better yields of 1,622.81 mg/l with highest specific productivity of 15 mg/l.h. Fermentation kinetics performed under different aeration and agitation conditions showed poly- ${\varepsilon}$-lysine fermentation to be a growth-associated production. A constant DO at 40% in the growth phase and 20% in the production phase increased the poly-${\varepsilon}$-lysine yield as well as cell mass to their maximum values of 1,992.35 mg/l and 20.73 g/l, respectively. The oxygen transfer rate (OTR), oxygen utilization rate (OUR), and specific oxygen uptake rates ($qO_2$) in the fermentation broth increased in the growth phase and remained unchanged in the stationary phase.

• Journal of information and communication convergence engineering
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• 제9권4호
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• pp.411-419
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• 2011

In this paper, we propose an Adaptive Regulating Drop (ARD) marker, as a novel dropping strategy at the ingressive edge router, to improve TCP fairness in assured services (ASs) without a decrease in the link utilization. To drop packets pertinently, the ARD marker adaptively changes a Temporary Permitted Rate (TPR) for aggregate TCP flows. The TPR is set larger than the current input IN packet rate of aggregate TCP flows while inversely proportional to the measured input OUT packet rate. To reduce the excessive use of greedy TCP flows by notifying droppings of their IN packets constantly to them without a decrease in the link utilization, the ARD marker performs random early fair remarking of their excessive IN packets to OUT packets at the aggregate flow level according to the TPR. In addition, an aggregate dropper is combined to drop some excessive IN packets fairly and constantly according to the TPR. Thus, the throughput of a TCP flow no more depends on only the sporadic and unfair OUT packet droppings at the RIO buffer in the core router. Then, the ARD marker regulates the packet transmission rate of each TCP flow to the contract rate by increasing TCP fairness, without a decrease in the link utilization.

• 한국환경보건학회지
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• 제22권1호
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• pp.57-64
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• 1996

The main objectives of this research program were to study the ozonation characteristics of phenol wastewater in the continuous packed colamn reactor(PCR) and the bubble column reactor (BCR) using ozone and to provide the fundamentals of ozonizing the phenol wastewater. Among various influencing factors that affect on phenol decomposition through the oxidation by ozone, contacting method, and ozone flow rate were chosen as reaction parameters. The results were obtained from two different types of contacting methods where the countercurrent flow was more efficient than the cocurrent flow in both the phenol removal efficiency and the ozone utilization efficiency. Furthermore, PCR showed the phenol removal efficiency 1.6 to 3% higher than that of BCR in both contacting methods, as well as the ozone utilization efficiency, suggesting that the countercurrent flow is more efficient than the cocurrent flow. The phenol removal efficiency and the ozone utilization efficiency were reduced in both reactors as the influent ozone flow rate increased. Upon varing flow rate from 0.5l/min to 2.0 l/min by 0.5 l/min, the phenol removal efficiency was reduced approximately from 8.5% to 10.5% and the ozone utilization efficiency was reduced approximately from 6% to 8% in both reactors. The performance of PCR was superior to that of BCR in the aspects of phenol removal and ozone utilization efficiency.

• 한국도서관정보학회지
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• 제36권2호
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• pp.327-348
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• 2005

본 연구의 목적은 서지정보검색시스템의 색인 정의의 중요성을 강조하고 최적 색인의 기초 자료를 마련하기 위함이다. 이를 위해 서지마크 데이터베이스로부터 색인 태그 정의 및 정규화를 통한 색인어추출이론에 대해 고찰하고, 이론에 따라 생성된 색인어의 검색 활용도를 분석하였다. 실험은 서지 2,200,488건에서 생성된 색인어 29,219,853건을 텍스트형 색인과 코드형 색인으로 나누어 이용자 왱 검색 로그에 나타난 색인 항목과 비교하여 어떤 색인 정의가 얼마나 활용되는가를 분석하였다. 결과에 따르면 서명, 저자, 출판사, 주제와 같은 텍스트형 색인어는 높은 검색 활용도를 보인 반면에 코드형 색인어는 검색 활용도가 낮아 검색에 활용되지 않는 불필요한 색인 정의들은 과감하게 제거하여 색인 정의를 최적화해야 함을 제안하였다.

• Journal of Preventive Medicine and Public Health
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• 제24권3호
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• pp.328-338
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• 1991

To find out the state of illness, patterns of medical care utilization, and factors which determine medical care utilization for aged we surveyed 679 rural old persons who live in the Chungnam province from Jan. 10 1991 to Jan. 19. The major findings of this study were as follows : 1. The morbidity rate of chronic illness during last 3 months was 56.4% for all surveyed old persons ; 58.7% for female and 52.8% for male. 2. As expected, 80 years old or above group showed the highest morbidity rate, 60.2% and the 65-69 years age group was the lowest, 50.5%. 3. Old persons who are householder, whose family income is less than 290,000 won per month, and who receive benifits from the public medical assistance program had relative higher morbidity rate than other groups and the difference was statistically significant (p<0.05). 4. The most frequent chronic illness was musculoskeletal disease, 49.6% ; the disease from which the aged had suffered for the longest period was gastrointestinal, 11.6yrs : the cerebrovascular was the disease which inflicts the lowest level of physical ability. 5. 67.1% of 383 persons who were suffering from chronic illness were in need of medical care but unmet ; among the remaining 32.9% who utilized medical care, 19.2% utilized it in local clinics or hospital OPD and 15% in th health centers or subcenters. 6. Old person who are married, whose sons are householder and whose family income is 500,000 won or above per month showed relative higher utilization rate than other groups and the difference was statistically significant (p<0.05). 7. The most common reason why the aged did not utilize, in spite of, need medical care was economic problem, 35.4%. For the aged whose family income per month is 500,000 won or above, however the most common reason was tolerable symptom, 46.9% while persons who answered economic problem were 6.1% of them, the lowest frequency.

• 통상정보연구
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• 제15권4호
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• pp.171-192
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• 2013

현재 우리나라의 FTA 활용률은 선진국의 경우에 비해 전반적으로 활용률이 낮다. 특히 한-ASEAN FTA의 경우 30% 대에 그치는 등 FTA 활용 제고가 시급한 과제로 부상하고 있다. 또한 무역기업이 FTA 특혜관세를 적용받는 비율도 저조한 것으로 평가되고 있어 활용률 제고가 최대 정책현안으로 나타나고 있다. 본 연구는 무역기업의 FTA 활용률을 높이기 위하여 실태분석을 실시하였다. 무역기업의 FTA 애로사항을 파악하였고, 무역기업의 FTA 활용교육과 컨설팅의 개선방안도 검토하였다. 이는 정부의 FTA 활용제고 시책 마련에 유용한 자료를 제공하는데 목적이 있다. 본 연구결과로 FTA를 활용한 무역기업의 수출확대, FTA 정책의 내실화, FTA 정책지지 기반강화에 기여할 것을 기대한다.

• Journal of Information Technology Applications and Management
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• 제15권3호
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• pp.127-152
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• 2008

This study sought to explore how SMEs are utilizing EC. Drawing on existing research on IT and EC related field, this study presented the framework of EC utilization level and analyzed its affecting factors in the point of organizational perspectives; strategy and competency. The impact of EC utilization on firm performance was also examined by employing BSC. Structural equation model was applied to test the relationships among the theoretical constructs with data from 171 SMEs. The results showed that the rate of EC utilization in SMEs is growing quite rapidly. However, manufacturing related firms still remain at a lower level compared to service related firms. As for the two affecting factors of EC utilization level, it was found that the level of EC utilization appeared to be driven not by strategy but by competency. This result implicates that EC utilization in SMEs doesn't reach to strategic purpose yet, while it is dependent on firm's competency. As far as the impact of EC utilization on firm performance, the study showed that the level of EC utilization has significant relationship with all perspectives performance indicators of BSC. This study can provide the managers with current EC utilization pattern and the guidelines as to where to put the efforts in the EC utilization and how to get an effective EC utilization strategy in the future.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제4권3호
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• pp.324-340
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• 2010

Video streaming service over wireless networks is a challenging task because of the changes in the wireless channel conditions that can occur due to interference, fading, and station mobility. To provide an efficient wireless video streaming service, the rate adaptation scheme should improve wireless node performance and channel utilization. Moreover, the quality adaptation scheme should be considered at the streaming application. To meet these requirements, we propose a new cross-layer design for video streaming over wireless networks. This design includes the rate and quality adaptation schemes. The rate adaptation scheme selects the optimal transmission mode and resolves the performance anomaly problem. Based on performance improvement by the proposed rate adaptation scheme, our quality adaptation scheme improves the quality of video streaming. Through performance evaluations, we prove that our cross-layer design improves the wireless channel utilization and the quality of video streaming.

• 한국통신학회논문지
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• 제21권5호
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• pp.1132-1140
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• 1996

In video coding systems, an effective rate control method is one of the most improtant issues for the good video quality. This paper presents an adaptive rate control scheme based on the buffer fullness, quantization, and buffer utilization for very low bit rate communication lines, such as 16kbit/s, 24bit/s, and so on. The strategy is implemented on H.263, whichis a vide coding algorithm for narrow band telecommunication channels up to 64kbit/s recommended by ITU-T SG15, to show the effectiveness. The simulation result shows that the suggested rate control scheme has better SNR performance and buffer utilization of source coder than those of linear and non-linear[9] buffer control strategies.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2002년도 봄 학술발표회 논문집
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• pp.157-164
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• 2002

Based on the results of prototype air-shaft construction, penetration capacity of RBM(Raise Boring Machine) was analyzed and compared with TBM(Tunnel Boring Machine) performance in this study. Utilization, down time, net penetration rate and advance rate were evaluated and compared. By conducting the laboratory tests for rock properties with the analysis of penetration capacity, relation of penetration capacity and geotechnical parameters was studied. The results showed that much more higher value of utilization, however lower value of net penetration rate for RBM was obtained compared to those of TBM. In addition, as the strength of rock penetrated increased, higher value of net penetration rate was obtained contrarily to the results of TBM performance. Finally, new relationship between total hardness and net penetration rate for weak and weathered rock was derived from these results.