• 제목/요약/키워드: Direct Observation

검색결과 618건 처리시간 0.025초

Identification of Salmonella spp. from porcine salmonellosis by matrix-assisted laser desorption ionization-time of flight mass spectrometry

  • Yang, Hyoung-Seok;Kim, Jae-Hoon
    • 한국동물위생학회지
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    • 제41권2호
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    • pp.105-110
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    • 2018
  • A total of 41 Salmonella (S.) strains were isolated from pigs suffered with severe watery diarrhea and were tried to identify by both matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) and polymerase chain reaction (PCR) analysis. Fibrinous exudate and ulceration in the large intestine were prevalent in gross observation, and variable degrees of enteritis were observed in the histology of large intestines. Subsequent polymerase chain reaction (PCR) analyses demonstrated that 41 strains were identified as S. Typhimurium (39 strains), though 2 stains were failed to identify. Further identification was performed using both direct smear and protein extraction method by MALDI-TOF MS analyses. In terms of extraction methods, 100% (41/41) of isolates were identified to species level of S. spp. Whereas only 43.9% (18/41) were identified to species level using the direct method. These results thus suggest that rapid and accurate diagnosis of porcine salmonellosis can be guaranteed by MALDI-TOF MS combined with protein extraction method.

최단 전압붕괴 임계점을 계산하는 알고리즘의 특성 비교 (Comparative Performance Study of Various Algorithms Computing the Closest Voltage Collapse Point)

  • 송충기;남해곤
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 1997년도 하계학술대회 논문집 D
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    • pp.1078-1082
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    • 1997
  • The distance in load parameter space to the closest voltage collapse point provides the worst case power margin and the left eigenvector identifies the most effective direction to steer the system to maximize voltage stability under contingency. This paper presents the results of the comparative performance study of the algorithms, which are applicable to a large scale power system, for computing the closest saddle node bifurcation (CSNB) point. Dobson's iterative method converges with robustness. However the slow process of updating the load increasing direction makes the algorithm less efficient. The direct method converges very quickly. But it diverges if the initial guess is not very close to CSNB. Zeng's method of estimating the approximate critical point in the pre-determined direction is attractive in the sense that it uses only using load flow equations. However, the method is found to be less efficient than Dobson's iterative method. It may be concluded from the above observation that the direct method with the initial values obtained by carrying out the iterative method twice is most efficient at this time and more efficient algorithms are needed for on-line application.

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Quantitative observation of co-current stratified two-phase flow in a horizontal rectangular channel

  • Lee, Seungtae;Euh, Dong-Jin;Kim, Seok;Song, Chul-Hwa
    • Nuclear Engineering and Technology
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    • 제47권3호
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    • pp.267-283
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    • 2015
  • The main objective of this study is to investigate experimentally the two-phase flow characteristics in terms of the direct contact condensation of a steam-water stratified flow in a horizontal rectangular channel. Experiments were performed for both air-water and steam-water flows with a cocurrent flow configuration. This work presents the local temperature and velocity distributions in a water layer as well as the interfacial characteristics of both condensing and noncondensing fluid flows. The gas superficial velocity varied from 1.2 m/s to 2.0 m/s for air and from 1.2 m/s to 2.8 m/s for steam under a fixed inlet water superficial velocity of 0.025 m/s. Some advanced measurement methods have been applied to measure the local characteristics of the water layer thickness, temperature, and velocity fields in a horizontal stratified flow. The instantaneous velocity and temperature fields inside the water layer were measured using laser-induced fluorescence and particle image velocimetry, respectively. In addition, the water layer thickness was measured through an ultrasonic method.

칼만 필터를 이용한 구조 안전성 모니터링에 관한 기초 연구 (A Basic Study on Structural Health Monitoring using the Kalman Filter)

  • 박명진;김유일
    • 대한조선학회논문집
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    • 제57권3호
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    • pp.175-181
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    • 2020
  • For the success of a structural integrity management, it is essential to acquire structural response data at some critical locations with limited number of sensors. In this study, the structural response of numerical model was estimated by data fusion approach based on the Kalman filter known as stochastic recursive filter. Firstly, transient direct analysis was conducted to calculate the acceleration and strain of the numerical standing beam model, then the noise signals were mixed to generate the numerical measurement signals. The acceleration measurement signal was provided to the Kalman filter as an information on the external load, and the displacement measurement, which was transformed from the strain measurement by using strain-displacement conversion relationship, was provided into the Kalman filter as an observation information. Finally, the Kalman filter estimated the displacement by combining both displacements calculated from each numerically measured signal, then the estimated results were compared with the results of the transient direct analysis.

Proteus sp. ST-1에 의한 Azo계 색소의 분해에 관한 연구 (The Study on Degradation of Azo Dyes by Proteus sp. ST-1)

  • 박형숙;하상태;이영근
    • 한국환경과학회지
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    • 제5권1호
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    • pp.71-81
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    • 1996
  • Direct Sky Blue-5B is an Azo dye known as general for staining of textile and leather, etc., and as materials which are difficult to be biodegraded in nature. The bacterium strain which could degrade direct Sky Blue-5B was isolated from activated sludge of dyeing factory and identified as Proteus sp. by experiment on morphological, cultural and biochemical characteristics, and so named Proteus sp. ST-1. The optimum condition of the strain for degradation of Sky Blue-5B were at about 35$^{\circ}C$ and PH 7~8. The strain had been capable of degradation with organic nitrogen effectively and had completely degraded 200mg/1 of the dye within 12hrs at 37$^{\circ}C$. The enzyme system related to degradation of Azo dye may be intracellular, and so degraded the dye after absorption into cell. The degradation products of Sky Blue-5B by Proton sp. 57-1 were analyzed by Gas Chromatography /Mass Spectrometry and Spectrophotomer, from this observation, it may be infered that the strain degraded the dye directly without any mediate.

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직접벡터제어에 의한 산업용 전동기의 구동시스템 구현 (Implementation of Industrial AC Motor Drive Using the Direct Vector Control)

  • 손진근;박종찬;문학룡;김병진;전희종
    • 조명전기설비학회논문지
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    • 제12권4호
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    • pp.81-89
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    • 1998
  • 본 논문에서는 유도전동기의 가변속 구동시 제어성능이 우수한 직접빽터 제어시스템에 관하여 연구하였다. 벡터제어시 펼요한 전동기의 자속정보는 궤환제어의 장점이 있는 자속연산형을 사용하여 구하였으며, 이때의 모델은 회전자 회로의 전류모델 방식을 이용하였다. 또한 회전자 좌표계에서의 자속관측기를 구성하여 고정 자 좌표계 사용시 나타날 수 있는 d-q축 간섭현상 및 이산화의 오차를 경감시켰다. 디지털 시율레이션올 통하여 원활한 제어특성이 나타남을 입증하였으며 고성능 DSP소자 및 고속 IGBT를 채용한 인버터 드라이브 시스템을 구현하여 그 특성을 확인하였다.

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Identification of structural systems and excitations using vision-based displacement measurements and substructure approach

  • Lei, Ying;Qi, Chengkai
    • Smart Structures and Systems
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    • 제30권3호
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    • pp.273-286
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    • 2022
  • In recent years, vision-based monitoring has received great attention. However, structural identification using vision-based displacement measurements is far less established. Especially, simultaneous identification of structural systems and unknown excitation using vision-based displacement measurements is still a challenging task since the unknown excitations do not appear directly in the observation equations. Moreover, measurement accuracy deteriorates over a wider field of view by vision-based monitoring, so, only a portion of the structure is measured instead of targeting a whole structure when using monocular vision. In this paper, the identification of structural system and excitations using vision-based displacement measurements is investigated. It is based on substructure identification approach to treat of problem of limited field of view of vision-based monitoring. For the identification of a target substructure, substructure interaction forces are treated as unknown inputs. A smoothing extended Kalman filter with unknown inputs without direct feedthrough is proposed for the simultaneous identification of substructure and unknown inputs using vision-based displacement measurements. The smoothing makes the identification robust to measurement noises. The proposed algorithm is first validated by the identification of a three-span continuous beam bridge under an impact load. Then, it is investigated by the more difficult identification of a frame and unknown wind excitation. Both examples validate the good performances of the proposed method.

직접 에너지 적층을 통한 STS316L 소재의 보수 공정에서 그루브 형상이 기계적 특성에 미치는 효과 (Effect of Groove Shapes on Mechanical Properties of STS316L Repaired by Direct Energy Deposition)

  • 오욱진;손용;손종윤;신광용;심도식
    • 소성∙가공
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    • 제29권2호
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    • pp.103-112
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    • 2020
  • This study explores the effects of different pre-machining conditions on the deposition characteristics and mechanical properties of austenitic stainless steel samples repaired using direct energy deposition (DED). In the DED repair process, defects such as pores and cracks can occur at the interface between the substrate and deposited material. In this study, we varied the shape of the pre-machined zone for repair in order to prevent cracks from occurring at the slope surface. After repairs by the DED process, macro-scale cracks were observed in samples that had been pre-machined with elliptic and trapezoidal grooves. In addition, it was not possible to completely prevent micro-crack generation on the sloped interfaces, even in the capsule-type grooved sample. From observation of the fracture surfaces, it was found that the cracks around the inclined interface were due to a lack of fusion between the substrate and the powder material, which led to low tensile properties. The specimen with the capsule-type groove provided the highest tensile strength and elongation (respective of 46% and 571% compared to the trapezoidal grooved specimen). However, the tensile properties were degraded compared to the non-repaired specimen (as-hot rolled material). The fracture characteristics of the repaired specimens were determined by the cracks at the sloped interfaces. These cracks grew and coalesced with each other to form macro-cracks, they then coalesced with other cracks and propagated to the substrate, causing final fracture.

소비 생활용품의 노출계수 조사 방법의 고찰 (Review of Exposure Assessment to Obtain Exposure Factors of Consumer Products)

  • 박지영;이기영;신호상;양원호
    • 한국환경보건학회지
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    • 제39권6호
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    • pp.532-540
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    • 2013
  • Background: Exposure factors for consumer products have been developed since the 1980s. Such exposure factors are important in risk assessment. Since the exposure/use patterns of consumer products in a country may reflect its respective cultural, meteorological, and socio-economic circumstances, unique Korean exposure factors for consumer products are needed. Such exposure factors are required for newly-enacted chemical regulations in Korea. For this review, published papers and survey reports on exposure factors of consumer products were examined for their assessment methodologies. Results: Investigation into exposure factors for consumer products used a variety of methods: home visit, online, telephone, and mail surveys using questionnaires; face to face interviews; modeling using a constructed database; and direct measurement. To collect more accurate exposure information or to check the reliability of the sampling method, some studies were repeated using the same questionnaire, in-home observation, direct measurement of usage, and videotaping. In Korea, nationwide exposure surveys were conducted five times over five years to obtain Korean exposure factors. However, with the exception of the $5^{th}$-year study, the surveys were online questionnaires and only the $5^{th}$-year study validated the accuracy of exposure information by re-visits and direct measurement. Conclusion: Accurate exposure factors are an essential part of risk assessment to assure safe use of consumer products. For better and safer management of consumer products, accurate exposure factors in Korea should be assessed for various exposure pathways.

임플란트와 상부보철물의 임상적/실험적 부적합 평가에 관한 문헌고찰 (A literature review on clinical/ laboratory misfit evaluation on implant-prosthesis)

  • 김종회;조웅래;고경호;허윤혁;박찬진;조리라
    • 대한치과의사협회지
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    • 제56권9호
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    • pp.462-478
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    • 2018
  • 임플란트와 지대주 간에 허용가능한 적합도를 넘는 부적합을 발견하고 이에 대처하는 것은 중요한 과제이다. 부적합을 임상에서 평가하고 발견하는 방법은 대부분 부적합의 정성적 평가에 치중하고 있으며 술자의 숙련도에 의존하고 있어 정확한 평가방법이라고 하기는 어렵다. 부적합의 정도를 판단하고 원인을 실험적으로 분석하는 방법 중 본 문헌고찰에서는 광탄성 분석법, 유한요소분석법, 스트레인게이지, 미생물 균체 분석 등 조건을 모형화하여 분석하는 모형화법과 사진 측량, 삼차원 좌표 측정, 현미경분석 및 방사선분석을 통해 부적합의 정도를 정밀하게 측정하는 수치법을 각각 설명하고 그 장단점 및 적용의 한계를 분석하였다. 지금까지 살펴본 실험실 부적합 평가 방법들을 장, 단점 및 정확도와 재현성을 기준으로 표로 정리한 것이 Table 3이다. 어떤 방법도 모든 경우에 적용할 수 있을 정도로 완벽하지는 않으므로 평가하고자 하는 부적합의 특성에 따라 적절한 평가방법을 선택하여 적용하는 것이 필요하다고 사료된다.

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