• Microbiology and Biotechnology Letters
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• v.40 no.2
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• pp.104-110
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• 2012

Glycosynthase is an active site nucleophile mutant enzyme, prepared from glycosidase, which is capable of synthesizing oligosaccharide derivatives without the hydrolysis of the product. Thermoacidophilic ${\alpha}$-glucosidase of Thermoplasma acidophilum (AglA) exhibits a transglycosylating activity yielding various glycosides. AglA was converted to glycosynthase by the substitution of the catalytic nucleophile Asp-408 residue into non-nucleophile glycine in order to increase its ability to synthesize various glycosides by transglycosylation. The glycosynthase mutant was purified by Ni-NTA chromatography and its glycoside-synthesizing activity was measured by using an external nucleophile, sodium formate buffer, providing maltose as a donor and p-nitrophenyl-${\alpha}$-D-glucopyranoside ($pNP{\alpha}G$) as an acceptor, respectively. In addition, $pNP{\alpha}G$ was examined for its feasibility to act as both a donor and an acceptor, and products were compared with those of the wildtype enzyme. The mutant enzyme was found to catalyze the formation of a specific product from $pNP{\alpha}G$ with a yield of 42.5% without further hydrolysis, while the wild-type enzyme produced two $pNP{\alpha}G$ products at low yields. The results demonstrate the possibility of satisfactory yields for the reactions in the presence of small amounts of acceptor, and demonstrate that the high activity of the mutant, at pHs below neutrality, was applicable in the transfer of glucose from the natural donor.

• Fire Science and Engineering
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• v.24 no.6
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• pp.1-6
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• 2010

A smoldering ground fire can be a probable cause of reignition of surface fire when transmitted from Fermentation layer to Humus layer with temperature higher than that of ignition. Purpose of this paper is to identify experimental methodology on the potential risk of a smoldering ground fire, which is similar to the real surface fuel bed, and its combustion characteristics. The fuel model designed in this study is composed of 3 layers such as Litter layer, Fermentation layer and Humus layer and 8 Thermocouples are set through 3 layer at each boundary and in between to detect the temperature change and duration of smoldering and propagation velocity. As a result, it was observed that ignition conditions in the boundary between L layer and F layer determined transmission and non-transmisstion to F-H layer. In addition, range of critical humidity at which a smoldering ground fire was transmitted in a material layer was 33~44% and when temperature exceeds $350^{\circ}C$, likelihood of transmission of a smoldering ground fire was high. In the research, the experimental model for multi-layer smoldering ground fire is suggested and information about propagation of smoldering fire, possibility of reignition according to moisture content, propagation velocity and temperature change are obtained, Also, the built-up methods were established to help analyze basic characteristics of smoldering ground fire.

• Korean Journal of Agricultural and Forest Meteorology
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• v.10 no.2
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• pp.35-46
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• 2008

Soil moisture is one of the important components in hydrological processes and also controls the subsurface flow mechanism at a hillslope scale. In this study, time series of soil moisture were measured at a hillslope located in Gwangneung National Arboretum, Korea using a multiplex Time Domain Reflectometry(TDR) system measuring soil moisture with bi-hour interval. The Box-Jenkins transfer function and noise model was used to estimate spatial distributions of soil moisture histories between May and September, 2007. Rainfall was used as an input parameter and soil moisture at 10 cm depth was used as an output parameter in the model. The modeling process consisted of a series of procedures(e.g., data pretreatment, model identification, parameter estimation, and diagnostic checking of selected models), and the relationship between soil moisture and rainfall was assessed. The results indicated that the patterns of soil moisture at different locations and slopes along the hillslope were similar with those of rainfall during the measurment period. However, the spatial distribution of soil moisture was not associated with the slope of the monitored location. This implies that the variability of the soil moisture was determined more by rainfall than by the slope of the site. Due to the influence of vegetation activity on soil moisture flow in spring, the soil moisture prediction in spring showed higher variability and complexity than that in early autumn did. This indicates that vegetation activity is an important factor explaining the patterns of soil moisture for an upland forested hillslope.

• Journal of the Korean Institute of Intelligent Systems
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• v.16 no.2
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• pp.164-171
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• 2006

Recently Digital multimedia broadcasting (DMB) has been available as a commercial service. The users sometimes have difficulty in finding their preferred multimedia contents and need to spend a lot of searching time finding them. They are even very likely to miss their preferred contents while searching for them. In order to solve the problem, we need a method for recommendation users preferred only minimum information. We propose an algorithm and a system for recommending users' preferred contents using preference transition probability from user's usage history. The system includes four agents: a client manager agent, a monitoring agent, a learning agent, and a recommendation agent. The client manager agent interacts and coordinates with the other modules, the monitoring agent gathers usage data for analyzing the user's preference of the contents, the learning agent cleans the gathered usage data and modeling with state transition matrix over time, and the recommendation agent recommends the user's preferred contents by analyzing the cleaned usage data. In the recommendation agent, we developed the recommendation algorithm using a user's preference transition probability for the contents. The prototype of the proposed system is designed and implemented on the WIPI(Wireless Internet Platform for Interoperability). The experimental results show that the recommendation algorithm using a user's preference transition probability can provide better performances than a conventional method.

• Annual Conference on Human and Language Technology
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• 2014.10a
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• pp.87-91
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• 2014

일반적인 기계학습 기반의 자연어처리 모듈의 개발에서 자질의 설계와 최적의 자질 조합을 구하는 작업은 많은 시간과 노력이 필요하다. 본 논문에서는 딥 러닝 기술을 전이 기반 방식의 한국어 의존 구문 분석에 적용하여 자질 튜닝 작업에 들어가는 많은 시간과 노력을 줄일 수 있음을 보인다. 또한 딥 러닝을 적용하기 위해 필요한 다양한 단어 표현(word embedding) 모델을 적용하여 최적의 단어 표현 모델을 알아내고, 성능 향상을 위해 최근에 개발된 Drop-out 및 Rectified Linear hidden Unit(ReLU) 기술을 적용한다. 실험결과, 기존 한국어 의존 구문 분석 연구들보다 높은 UAS 90.37%의 성능을 보였다.

• Proceedings of the Korean Information Science Society Conference
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• 2000.04a
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• pp.558-560
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• 2000

본 논문은 ATM(Abstract Timed Machine)에 대해서 기술한다. ATM 은 임무 위급 시스템과 같은 실시간 시스템을 명세, 분석 및 검증할 수 있는 정형 기법이다. ATM 은 모드(mode), 전이(transition), 포트(port)로 구성된다. 모드는 머신의 압축된 상태를 의미하고 전이는 모드와 모드 사이의 변화를 말한다. 포트는 ATM 들 사이의 상호작용을 위한 진입을 나타내기 위한 것이다. ATM 은 소프트웨어 순환 공학을 위해 디자인 되었다. ATM은 재/역공학적 측면에서 계산 이론과 더불어 기존의 실시간 시스템의 소스코드에 대한 디지안 및 환경 정보를 나타낸다. 본 논문은 병렬성, 병렬적으로 동작하는 엔터티들 사이의 제어 정보이 흐름, ATM 타입과 클래스로부터의 인스턴스, 비/동기적 이벤트, 포트와 이벤트 타입, 포트의 타입, 통신, 입/출력, 예외처리, 시간에 관한 요구사항, 다수를 대상으로 하는 통신 주기적 작업등과 같은 ATM의 여러 개념을 기술하고 이러한 속성들을 Producer-Buffer-Consumer 예제로 살펴본다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 1999.11a
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• pp.294-299
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• 1999

CCSR은 CCS에 시간적인 개념이 추가된 실시간 명세 언어로 실시간 프로세스의 정적 분석에 이용되고 있다. CCSR은 프로세스 전이 규칙을 이용하여 프로세스 동작의 관심 부분만 하여 분석하기 때문에 전체 태스크(task)의 동작을 분석하는데 적용하기 어렵고, 전이규칙에 따른 상태 변화를 이해하기 어렵다. E-TCPN은 시간 요소가 첨가된 Petri Net의 변형된 형태로 실시간 시스템의 분석과 모델링을 위한 형식적(formal) 방법을 제공한다. 본 논문에서는 CCSR로 표현된 프로세스 동작을 E-TCPN 모델에 적용함으로써 실시간 시스템을 중요한 사건을 중심으로 전체 태스크의 동작 과정을 표현하고 프로세스의 수행 과정을 이해하기 쉽도록 CCSR을 변형하여, E-TCPN 명세 모델에 적용하고, 적용된 E-TCPN으로 스케줄링가능성 분석 알고리즘을 제안하고 구현하였다.

• Transactions of the Korean hydrogen and new energy society
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• v.30 no.2
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• pp.103-110
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• 2019

Cu-Zn-Al catalysts were prepared via co-precipitation method for low-temperature water-gas shift (LT-WGS) reaction under practical reaction condition. Aging time was systematically changed to find optimum point for LT-WGS under practical condition. The Cu-Zn-Al catalyst aged for 72 hours showed the highest CO conversion within low-temperature range as well as very stable catalytic activity for 200 hours despite the practical reaction condition.

• Proceedings of the Korea Information Processing Society Conference
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• 2013.05a
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• pp.792-795
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• 2013

본 연구에서는 조영증강 의료 초음파 영상에서 조영제의 도달시간(arrival time)과 전이시간(transit time)에 관한 정보를 영상화하는 과정에서 정보의 왜곡을 개선하는 방법론을 제시한다. 간 질환 진단을 위한 파라미터 영상에서 병변 형태의 왜곡은 호흡에 의한 흔들림 현상과 노이즈의 영향에 기인한다. 본 논문에서는 이를 개선하는 방법으로서 MRF(Markov Random Field) 모델을 적용한 최적화 기법을 제안한다. 이를 위하여 Gibbs 샘플러를 적용하기 위한 에너지 함수를 정의하고 이를 기반으로 하는 영상개선 알고리즘을 구현하였다. 제안된 이론은 실제 의료진단 데이터에 적용함으로써 그 유용성을 평가하였다.

• Journal of IKEEE
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• v.26 no.4
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• pp.639-646
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• 2022

In this paper, to solve the large dataset problem, we collect images through an image collection method called web crawling and build datasets for use in image classification models through a data preprocessing process. We also propose a lightweight model that can automatically classify images by adding category values by incorporating transfer learning into the image classification model and an image classification model that reduces training time and achieves high accuracy.