• Microbiology and Biotechnology Letters
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• v.48 no.4
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• pp.525-532
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• 2020

A continuous fermentation process was carried out to enhance hyaluronic acid (HA) production using Streptococcus zooepidemicus cells. During the 1st stage continuous operation from 8 h with a dilution rate of 0.029/h (D1), HA was produced in the range of 7.5-10 g/l. During the 2nd stage from 44 h with a dilution rate of 0.036/h (D2), HA production (8.28 g/l) was initially reduced to a small extent due to increase of dilution rate from D1 to D2, and then a new pseudo-steady state was formed within a few hours with a concurrent small variations of HA production. The HA amount produced during the latter part of the 2nd stage was stably maintained in the range of 8.28-9.48 g/l, about 4.7% less amount compared to the 1st stage. Due to 24% increase of dilution rate from D1 to D2, however, maximum volumetric productivity (DP) amounting to 0.341 g/l/h was obtained at 96 h during the 2nd stage. This maximum productivity obtained from the continuous culture turned out only a small increase (3%) as compared to the corresponding batch fermentation. However, it should be noted that, in the case of batch process, one run typically consists of serial stages of growth culture plus one final production culture. This implies that, if the continuous fermentation that practically needs no dead time necessary for the multi-stage growth cultures is run for longer period, the total amount of the accumulated HA would be far greater than the amount obtained from the corresponding batch culture performed for the identical period.

• Journal of the Korean GEO-environmental Society
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• v.15 no.4
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• pp.37-41
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• 2014

Pulse electrokinetic technology is proposed for improving the dewatering-process from clay-sandy soil. Proposed electrokinetic technology is to be the dewatering process due to fluid movement of current flow for the stability of clay-sandy soils. Samples produced in this study were completed to verify the proposed performance for 7 days by gradually increasing the pressure to the final pressure of 30 psi ($2.11kgf/cm^2$) through the compression process. In this study, pulse electrokinetic treatment and conventional continuous electrokinetic treatment are tested and observed, respectively. The condition of continuous electrokinetic treatment is a continuous process during 48 hours. And the condition of pulse electrokinetic treatment system is to interrupt the power three times for 48 hours, every 8 hours. These treatments are that the voltage gradient is 3 V/cm. As a result, the efficiency of pulse electrokinetic is similar to the continuous electrokinetic. The power consumption efficiency of pulse electrokinetic is better than continuous electrokinetic.

• The Korean Journal of Rheology
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• v.8 no.2
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• pp.103-118
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• 1996

변형된 Maxwell 모델을 모의 데이터와 폴리스티렌의 동적 실험 데이터인 G＇과 G ＂에 적용하여 연속 완화시간 스펙트럼을 결정하였고, Maxwell 모델을 사용했을 때 얻어지 는 불연속 완화시간 스펙트럼과 비교하였다. MGMM과 GMM 모두 선형회귀 방법과 비선 형회귀 방법을 사용하여 완화시간 스펙트럼을 결정하였는데 비선형 방법을 사용했을 때 선 형방법에 비해 좀 더 만족스러운 결과를 얻을수 있었다. 모의 데이터의 경우 사용한 완화시 간의 수가 많은 경우에는 MGMM과 GMM 모두 원래의 스펙트럼을 잘 재현했으나 완화시 간의 수가 작은 경우에는 MGMM이 GMM에 비해 원래의 완화시간 스펙트럼을 보다 잘 나 타내었다. 또 단분산성폴리스티렌의 경우 MGMM과 GMM의 완화시간 스펙트럼이 모두 작 은 완화시간 영역에서는 분자량에 무관했고 큰 완화시간 영역에서는 분자량이 커질수록 스 펙트럼이 완화시간이 커지는 쪽으로 이동하였다. 또 두드러진 terminal 완화시간을 볼수 있 었다. 그러나 다분산성 폴리스티렌의 경우에는 단분산성의 경우와는 달리 두드러진 terminal 완화시간을 볼수 없었다. 그리고 MGMM의 파라미터 m은 분자량 분포에 크게 의존함을 알 수 있었으며 연속 완화시간 스펙트럼에서 계산된 불연속 완화시간 스펙트럼이 GMM에서 얻어진 불연속 완화시간 스펙트럼과 잘 일치함을 볼수 있었다.

• Proceedings of the Korean Society of Disaster Information Conference
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• 2017.11a
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• pp.267-270
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• 2017

기능연속성계획(Continuity of Operation, COOP)은 지진, 태풍, 산사태 등과 같은 자연재난, 전염병 확산 및 테러 등의 사건과 대형사고, 공급망 단절, 돌발적인 경영환경의 변화 등과 같은 다양한 사회재난의 발생으로 중요한 기능이 중단되지 않도록 하고, 중요한 기능이 중단된 경우에는 목표로 하는 복구시간 내에 기능을 재개시키며, 기능중단에 따른 위험을 최소화시키기 위해 정책, 제도 및 절차 등을 계획하는 것이다. 본 논문에서는 지방자치단체의 기능연속성 계획 수립적용에 관해 ${\bigcirc}{\bigcirc}$시를 기준으로 구축방안을 모색하였다. 이를 통해 ${\bigcirc}{\bigcirc}$시의 기능연속성 구축의 수립기준을 수립절차에 따라 나타내었다.

• KIPS Transactions on Computer and Communication Systems
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• v.3 no.10
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• pp.377-382
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• 2014

Analysis techniques of the data over time from the mobile environment and IoT, is mainly used for extracting patterns from the collected data, to find meaningful information. However, analytical methods existing, is based to be analyzed in a state where the data collection is complete, to reflect changes in time series data associated with the passage of time is difficult. In this paper, we introduce a method for analyzing multi-block streaming data(AM-MBSD: Analysis Method for Multi-Block Stream Data) for the analysis of the data stream with multiple properties, such as variability of pattern and large capacitive and continuity of data. The multi-block streaming data, define a plurality of blocks of data to be continuously generated, each block, by using the analysis method of the proposed method of analysis to extract meaningful patterns. The patterns that are extracted, generation time, frequency, were collected and consideration of such errors. Through analysis experiments using time series data.

• The Korean Journal of Financial Management
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• v.20 no.1
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• pp.213-231
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• 2003

This paper uses the Efficient Method of Moments(EMM) of Gallant and Tauchen to estimate continuous-time stochastic volatility diffusion model for the Korean Composite Stock Price Index, sampled daily over $1995\sim2002$. The estimates display non-normality of stock index return, leptokurtic distribution, and stochastic volatility. Funker, this study suggests that two factor stochastic volatility model will be more desirable than one factor stochastic volatility model to estimate daily Korean stock return and also suggests that the stochastic volatility diffusions should allow for Poisson jumps of time-varying intensity.

• Geophysics and Geophysical Exploration
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• v.20 no.3
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• pp.176-184
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• 2017

To interpret the seismic image precisely, random noises should be suppressed and the continuity of the image should be enhanced by using the appropriate smoothing techniques. Structure-Oriented Filter-Edge Preserving (SOF-EP) technique is one of the methods, that have been actively researched and used until now, to efficiently smooth seismic data while preserving the continuity of signal. This technique is based on the principle that diffusion occurs from large amplitude to small one. In a continuous structure such as a horizontal layer, diffusion or smoothing is operated along the layer, thereby increasing the continuity of layers and eliminating random noise. In addition, diffusion or smoothing across boundaries at discontinuous structures such as faults can be avoided by employing the continuity decision factor. Accordingly, the precision of the smoothing technique can be improved. However, in the case of the structure-oriented semblance technique, which has been used to calculate the continuity factor, it takes lots of time depending on the size of the filter and data. In this study, we first implemented the SOF-EP method and confirmed its effectiveness by applying it step by step to the field data. Next, we proposed and applied the corner response method which can efficiently calculate the continuity decision factor instead of structure-oriented semblance. As a result, we could confirm that the computation time can be reduced by about 6,000 times or more by applying the corner response method.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 1993.04a
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• pp.275-281
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• 1993

본 발표에서는 신경회로망을 이용하여 연속음성중에서 키워드를 인식하는 방법을 설명한다. 연속음성에서 파형소편 및 음절을 식별하는 휴리스틱 알고리즘을 개발하였고, 연속음성을 음절단위로 파형소편 스펙트럼분석(선형예측법)으로 특성치를 추출하였다. 음절의 특성치는 코호넨 신경회로망을 통하여 학습을 시켰으며, 연속음성중 키워드인식은 먼저 음절을 인식하여 단어를 찾고, 인식된 단어가 키워드와 일치하는가를 확인한다. 본 연구의 의의는 파형소편 및 음절식별 알고리즘을 통하여, 크기불변성(Scaling invariance), 시간불변성(Time warping 및 Time-shift invariance), 중복성제거의 문제점을 해결하였고, 신경회로망의 학습을 통하여 화자독립적인 연속음성인식시스템 구축의 기반을 확립한데 있다. 본 음성인식모델은 학교구내 전화번호 안내시스템으로 활용단계에 있으며 전화번호뿐만아니라 주소안내시스템으로도 활용될 예정이다. 또한 자동차 운전보조시스템 및 주행안내시스템의 음성명령에 응용될 수 있는데, 예로 음성명령은 "핸들 좌로 20도", "시청까지 주행", "시청 지도안내"등이 될 수 있다. 현재 자동차 운전보조시스템은 컴퓨터 화면상 모의동작시스템으로 운영되고 있다. 본 음성인식모델은 화자종속시 90%이상, 화자독립시 70%의 인식결과를 보였다.시 90%이상, 화자독립시 70%의 인식결과를 보였다.

• Journal of the Institute of Convergence Signal Processing
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• v.3 no.2
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• pp.1-7
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• 2002

Since multimedia data such as video and audio data are displayed within a certain time constraint, their computation and manipulation should be handled under limited condition. Traditional real-time scheduling algorithms could not be directly applicable, because they are not suitable for multimedia scheduling applications which support many clients at the same time. Rate Regulating Proportional Share Scheduling Algorithm is a scheduling algorithm considered the time constraint of the multimedia data. This scheduling algorithm uses a rate regulator which prevents tasks from receiving more resource than its share in a given period. But this algorithm loses fairness, and does not show graceful degradation of performance under overloaded situation. This paper proposes a new modified algorithm, namely Modified Proportional Share Scheduling Algorithm considering the characteristics of multimedia data such as its continuity and time dependency. Proposed scheduling algorithm shows graceful degradation of performance in overloaded situation and the reduction in the number of context switching. Furthermore, a new evaluation method is proposed which can evaluate the flexibility of scheduling algorithm.

• Proceedings of the KAIS Fall Conference
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• 2011.05a
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• pp.347-350
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• 2011

본 논문에서는 습식식각 설비의 Process 동작 간에 발생되는 설비의 비 가동 시간을 최소화하여 Throughput을 향상시키기 위하여 Monitoring 한 결과 Recipe 변경, 액 교환 발생, Tact 변경 등의 공정간 조건에 따라 대기시간이 발생(생산 지연시간 발생) 하는 것을 확인 하고 이를 개선하기 위한 연구이다. 연구 방법으로, Recipe Data 적용 시점을 약액 구간 처리 완료 시점에서 후속 기판이 대기하지 않고 연속 투입을 실시, Chamber Drain과 약액 Tank 전환이 동시에 이루어지고 액 교환 동작 중 Pump Spray의 연속성을 유지하는 무정지 액 교환 Sequence 적용, Tact 적용 시점을 전 기판 배출 확인 후 실시하는 것을 약액 구간 처리 완료 후 적용의 3가지 방법을 6시그마의 DMAIC 기법을 활용하였다. 연구 결과 개선 전 비 가동 시간이 설비 대당 1일 28분 시그마 Level 3.40 이었던 것을 개선 후 설비 대당 1일 17분 시그마 Level 5.3 으로 개선됨을 확인 할 수 있다.