• Journal of Microbiology and Biotechnology
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• 제24권8호
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• pp.1073-1080
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• 2014

A total of 10 cellulase-producing bacteria were isolated from soil samples irrigated with paper and pulp mill effluents. The sequencing of 16S rRNA gene revealed that all isolates belonged to different species of genus Bacillus. Among the different isolates, B. subtilis IARI-SP-1 exhibited a high degree of ${\beta}$-1,4-endoglucanase (2.5 IU/ml), ${\beta}$-1,4-exoglucanase (0.8 IU/ml), and ${\beta}$-glucosidase (0.084 IU/ml) activity, followed by B. amyloliquefaciens IARI-SP-2. CMC was found to be the best carbon source for production of endo/exoglucanase and ${\beta}$-glucosidase. The ${\beta}$-1,4-endoglucanase gene was amplified from all isolates and their deduced amino acid sequences belonged to glycosyl hydrolase family 5. Among the domains of different isolates, the catalytic domains exhibited the highest homology of 93.7%, whereas the regions of signal, leader, linker, and carbohydrate-binding domain indicated low homology (73-74%). These variations in sequence homology are significant and could contribute to the structure and function of the enzyme.

• Journal of Applied Biological Chemistry
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• 제56권2호
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• pp.61-67
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• 2013

Due to their diversity and abundancy, marine resources have emerged as important biological resources to compensate the limited sources of terrestrial biological materials. Phaeodactylum tricornutum (PT) is one of classical model diatoms most widely studied for its ecology, physiology, biochemistry and molecular biology. In this study, four different PT extracts on lipopolysaccharide (LPS)-stimulated macrophages were compared for anti-inflammatory effect and investigated for the underlying mechanisms. The extracts of PT inhibited nitric oxide production from LPS stimulated RAW 264.7 cells in a dose dependent manner. These extracts also inhibited the expression of mRNA and production of proteins of pro-inflammatory cytokines such as interleukin (IL)-$1{\beta}$, IL-6 and tumor necrosis factor-${\alpha}$. These inhibitory effects were found to be caused by blockage of nuclear factor-${\kappa}B$ activation and phosphorylation of p38 mitogen-activated protein kinases, extracellular signal-regulated kinases 1 and 2 and c-Jun N-terminal kinase.

• 한국항공운항학회지
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• 제18권4호
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• pp.59-66
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• 2010

Aerospace structures need high stability and long life because many personal injuries can result from an accident and securing structural integrity for various external environments is more important than any other thing. So first of all we must prove the destruction properties for operating environment, have prediction technology about damage evolution and life, and develop an economical non-destructive technology capable of detecting structure damage. Acoustic emission (AE) have no need of artificial environment like ultrasonic inspection or radio fluoroscopy to emit a certain energy, is a testing technique using seismic signal resulting from interior changes of solids, and enables to observe if any fault is appeared and it grows seriously or not while running. In this study we suggest the method of structural integrity evaluation for aerospace structures through the acoustic emission technique, for which a model plane was manufactured and an actual operation test was conducted.

• Journal of Biosystems Engineering
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• 제14권1호
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• pp.1-7
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• 1989

This study was carried out to develop a system and methodology to simulate the engine load variation occuring during agricultural field operations for a laboratory engine test. The system consisted of an electric dynamometer, an Apple II microcomputer, and a data acquisition and control system. Several pieces of instruments were utilized to measure various engine performance data. Both engine torque and engine speed were fully controlled by a computer program. The dynamic characteristics of the system were analyzed through a series of tests and the limitations on the load simulation test were presented. The results of the study are summarized as follows: 1. Engine speed and toque were controlled by a computer program. The use of a stepping motor and reduction gears enabled engine speed be controlled within 1 rpm. 2. The natural frequency of the dynamometer-engine system was found to be around 5 Hz, at which the load simulation would be impossible because of resonance. 3. For the harmonic inputs with the frequencies above the natural frequency, the signal attenuated too much and therefore the load simulation was impossible. 4. The step response of the system showed an overshoot of 24.5 percent and the settling time for 5 percent criterion was around 3 seconds. 5. When actual field test data are utilized for load simulation, a low-pass filter should be included to attenuate the frequency components around and above the natural frequency.

• 한국자동차공학회논문집
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• 제17권4호
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• pp.16-23
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• 2009

Driving simulators are useful tools not only to test the components of future cars but also to evaluate the telematics service and HMI (Human-Machine Interface). However driving simulators cannot be implemented to test and evaluate the telematics service system because the GPS (Global Positioning System) which contains basic functional support for the telematics module do not work in the VR (virtual reality) environment. This paper presents a method to implement telematics service to a driving simulator by developing the GPS simulator which is able to emulate GPS satellite signals consist of NMEA-0183 protocol and RS232C communication standards. It is expected that the driving simulator with the GPS simulator can be used to study HMI and human-factor evaluations of the commercial telematics system to realize the HiLES (Human-in-the-Loop Evaluation System).

• 한국방송∙미디어공학회:학술대회논문집
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• 한국방송공학회 2013년도 하계학술대회
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• pp.274-277
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• 2013

CT(Computed Tomography)영상에서 선량과 화질은 중요한 요소이다. 선량은 환자에게 직접적으로 악영향을 끼치는 요소이며, 화질은 환자의 병변을 판단하는데 매우 중요하게 작용한다. 반복적 재구성 알고리즘을 이용하면 저선량 영상에서도 고화질의 영상을 얻을 수 있는지 FBP와 정량적, 정성적으로 비교하였다. 촬영 프로토콜은 관전압 80, 100, 120kVp에서 관전류를 동일하게 200mA로 촬영하여 획득하였으며, 정량적 평가를 위해 SD(Standard Deviation), SNR(Signal to Noise Ratio), MTF(Modulation Transfer Function)를 측정하여 분석하였다. 선량은 80kVp일 때 가장 낮았으며, 120kVp일 때 가장 높았다. 80kVp의 영상을 Toshiba 사(社)의 AIDR 3D(Adaptive Iterative Reduction integrated into $^{SURE}Exposure$)로 재구성하고, 120kVp의 영상에 FBP로 재구성한 다음 정량적 비교를 한 결과 AIDR 3D를 적용한 영상의 SD가 낮게 나왔으며, SNR이 높게 나타났고, MTF 곡선은 유사하게 나타났다. 그리고 FWHM(Full Width at Half Maximum) 값의 오차가 거의 없었다. 결론적으로 AIDR 3D는 저선량에서도 높은 화질을 나타냄을 확인하였다.

• 대한의용생체공학회:의공학회지
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• 제30권4호
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• pp.327-332
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• 2009

In this paper, new index was developed to estimate the depth of anesthesia during general anesthesia using EEG. Analysis of the power spectral density(PSD) of EEG was used to develop new parameters because EEG signal tends to have slow wave during anesthesia. Classifier for index creator was developed by using SEF, BDR and BTR parameters, which are calculated by power spectral density. EEG data were obtained from 7 patients (ASA I, II) during general anesthesia with Sevoflurane. The anesthetic depth evaluation indexes ranged from 0 to 100. The average were $86.05{\pm}10.1$, $36.98{\pm}20.2$, $15.33{\pm}13.6$, $50.87{\pm}16.5$ and $87.72{\pm}11.7$ for the states of pre-operation, induction of anesthesia, operation, awaked and post-operation, respectively. The results show that while the depth of anesthesia was evaluated, more accurate information can be provided for anesthetician.

• 한국항행학회논문지
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• 제6권3호
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• pp.223-230
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• 2002

본 논문에서는 MSSI 보상 기법을 채택한 2,000km 광 전송 시스템의 수신 성능 평가를 위해 신호간의 간섭 영향을 고려한 직접 검파 수신단에서의 잡음 전력과 비트 에러율을 도출하고, 비트율에 따른 수신 감도를 계산해 보았다. 본 논문에서 제안한 BER 계산이 실제 시스템에 적용될 수 있는 방법이라는 것을 확인할 수 있었고, 전송 링크에 MSSI 보상 기법이 적용된 시스템에서 신호 파형의 색 분산과 비선형 효과에 의한 왜곡이 보상되지만, 결국 비트율이 높아질수록 좁아지는 비트 간격에 따른 ISI에 의해 평균 수신 전력의 감소를 가져오고 궁극적으로 수신 감도를 감소시켜 준다는 것을 확인할 수 있었다.

• Structural Engineering and Mechanics
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• 제64권6권
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• pp.803-817
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• 2017

Structural health monitoring has increasingly been a focus within the civil engineering research community over the last few decades. With increasing application of sensor networks in large structures and infrastructure systems, effective use and development of robust algorithms to analyze large volumes of data and to extract the desired features has become a challenging problem. In this paper, we grasp some precautions and key points of the signal processing approach, wavelet, establish a relative reliable framework, and analyze three problems that require attention when applying wavelet based damage detection approach. The cases studies how to use optimal scales for extracting mode shapes and modal curvatures in a reinforced concrete beam and how to effectively identify damages using maximum curves of wavelet coefficient differences. Moreover, how to make a recognition based on the wavelet multi-resolution analysis, wavelet packet energy, and fuzzy sets is a meaningful topic that has been addressed in this work. The relative systematic work that compasses algorithms, structures and evaluation paves a way to a framework regarding effective structural health monitoring, orientation, decision and action.

• 한국음향학회지
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• 제18권5호
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• pp.63-67
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• 1999

최근 들어 실내음향 특성의 측정과 평가를 위해 백색잡음을 이용한 잔향시간 측정법 대신에 임펄스응답을 이용한 측정법이 널리 이용되고 있다. 이 방법은 재현성이 우수하고 다양한 실내음향 특성치들을 한꺼번에 산출할 수 있어 전통적인 잔향시간 측정법에 비해 여러 가지 장점을 가지고 있다. 본 연구에서는 MLS(Maximum Length Sequence) 신호를 이용하여 실내에서의 임펄스 응답을 측정하고 이를 후처리(post-processing) 하여 잔향시간(EDT, RT), 명료도 지수(C50, C80, D, U50, U80, AI), 음의 크기 지수(G) 등, 주로 실의 음성음향 성능을 측정하는 시스템을 구축하였다. 본 연구에서는 측정시스템과 후처리 프로그램의 구성, 몇몇 실내공간에 대한 시험 측정의 결과 및 고찰 등에 대해 소개하고자 한다.