• Geomechanics and Engineering
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• 제15권6호
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• pp.1207-1217
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• 2018

Geomechanics parameters are critical to numerical simulation, stability analysis, design and construction of geotechnical engineering. Due to the limitations of laboratory and in situ experiments, back analysis is widely used in geomechancis and geotechnical engineering. In this study, a hybrid back analysis method, that coupling numerical simulation, response surface (RS) and relevance vector machine (RVM), was proposed and applied to identify geomechanics parameters from hydraulic fracturing. RVM was adapted to approximate complex functional relationships between geomechanics parameters and borehole pressure through coupling with response surface method and numerical method. Artificial bee colony (ABC) algorithm was used to search the geomechanics parameters as optimal method in back analysis. The proposed method was verified by a numerical example. Based on the geomechanics parameters identified by hybrid back analysis, the computed borehole pressure agreed closely with the monitored borehole pressure. It showed that RVM presented well the relationship between geomechanics parameters and borehole pressure, and the proposed method can characterized the geomechanics parameters reasonably. Further, the parameters of hybrid back analysis were analyzed and discussed. It showed that the hybrid back analysis is feasible, effective, robust and has a good global searching performance. The proposed method provides a significant way to identify geomechanics parameters from hydraulic fracturing.

• Reproductive and Developmental Biology
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• 제34권3호
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• pp.257-262
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• 2010

The purpose of this study is to establish a basic culture system enabling in vitro culture of chicken blastodermal cells and to test the feasibility of retrovirus-mediated gene transfer to the cultured cells. The blastodermal cells were isolated from freshly laid eggs of stage X and cultured with or without STO feeder layer cells. Stem cell-like morphology was maintained after multiple passages and RT-PCR analysis proved expression of several stem cell specific genes. Immunocytochemical analysis using antibodies of anti-EMA-1 and anti-SSEA-1 also showed the feature of stem cells. Infection of the cultured blastodermal cells with LNCGW retrovirus vector resulted in successful transfer of foreign genes. The results of this study may be useful in establishing stem cell-mediated transgenic chicken production.

• 한국자동차공학회논문집
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• 제5권4호
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• pp.171-178
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• 1997

Vehicle interior noise has become increasingly important in this recent years. The noise of a vehicle is one of the important problems in a vehicle design. The interior noise is caused by various vibration sources of vehicle compartment. The booming noise of a vehicle can be significantly affected by vibrations transmitted from engine excitation forces to the vehicle body. Specially, we are interested in the state of transmission paths such as engine mounts to reduce noise in a vehicle compartment. In this paper, we have been calculated the contribution of each transmission path such as engine mounts to interior noise. To identify contribution of each input sources and transmission paths to output, the effectiveness of each input component to output is calculated. Sensitivity analysis is carried out for investigation of contribution to output due to input variations. With the simulation of magnitude and phase change of inputs using vector synthesis diagram, the trends of synthesized output vector are obtained. As a result, we suggested sensitivity analysis of vector synthesis as a technique of prediction and control for noise in a vehicle compartment.

• Journal of Astronomy and Space Sciences
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• 제29권3호
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• pp.287-293
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• 2012

Satellite operating agencies are constantly monitoring conjunctions between satellites and space objects. Two line element (TLE) data, published by the Joint Space Operations Center of the United States Strategic Command, are available as raw data for a preliminary analysis of initial conjunction with a space object without any orbital information. However, there exist several sorts of uncertainties in the TLE data. In this paper, we suggest and analyze a method for estimating the uncertainties in the TLE data through mean, standard deviation of state vector residuals and covariance matrix. Also the estimation results are compared with actual results of orbit determination to validate the estimation method. Characteristics of the state vector residuals depending on the orbital elements are examined by applying the analysis to several satellites in various orbits. Main source of difference between the covariance matrices are also analyzed by comparing the matrices. Particularly, for the Korea Multi-Purpose Satellite-2, we examine the characteristics of the residual variation of state vector and covariance matrix depending on the orbital elements. It is confirmed that a realistic consideration on the space situation of space objects is possible using information from the analysis of mean, standard deviation of the state vector residuals of TLE and covariance matrix.

• Journal of Positioning, Navigation, and Timing
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• 제9권3호
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• pp.207-214
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• 2020

In this paper, we implement linear-quadratic-Gaussian based vector tracking loop (LQG-VTL) instead of conventional extended Kalman filter based vector tracking loop (EKF-VTL). The LQG-VTL can improve the performance compared to the EKF-VTL by generating optimal control input at a specific performance index. Performance analysis is conducted through two factors, frequency thermal noise and frequency dynamic stress error, which determine total frequency tracking error. We derive the thermal noise and the dynamic stress error formula in the LQG-VTL. From frequency tracking error analysis, we can determine control gain matrix in the LQG controller and show that the frequency tracking error of the LQG-VTL is lower than that of the EKF-VTL in all C/N0 ranges. The simulation results show that the LQG-VTL improves performance by 30% in Doppler tracking, so the LQG-VTL can extend pre-integration time longer and track weaker signals than the EKF-VTL. Therefore, the LQG-VTL algorithm is more robust than the EKF-VTL in weak signal environments.

• 한국소음진동공학회논문집
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• 제17권12호
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• pp.1254-1261
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• 2007

The structure has several types of noise and booming noise of a vehicle is usually caused by the vibration of the vehicle's body transmitted from the engine through the mounting system. Vector synthesis analysis is performed to predict the booming noise when the characteristic of the engine mounting system is changed., i.e., when magnitudes and phases of vibratory forces after the mounts are altered. To use this method effectively, the concept of Multi-dimensional-analysis and Experimental Design are introduced to identify the contributions of each vibration sources and transmission paths to interior noise. It was used 3inputs/1output system and found the magnitudes and phases of the forces for minimizing the noise. Finally, the synthesized interior booming noise level is predicted by the vector synthesis diagram. It is shown that the vector synthesis method can be used to obtain the optimum design characteristic of the mounting system to control the interior booming noise of a vehicle.

• 전산구조공학
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• 제9권2호
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• pp.115-120
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• 1996

구조물의 동적해석의 주된 관점은 적은 갯수의 모우드형상과 계산과정으로 적정정도의 해를 구하는 것이다. Component mode method는 부분구조물 기법을 이용하여 자유도를 줄이는 방법을 이용하였으나 동하중의 특성이 고려되지 않는 단점이 있으며 이를 보완하기 위한 Ritz Vector법은 많은 반복연산이 필요하며 오차가 가중되는 단점이 있다. 본 연구에서는 Component mode method의 효율성을 개선시키고자 기존의 장점을 유지하면서 직접적분과정에서의 계산량을 현저히 줄일 수 있는 Lanczos 알고리즘을 도입하였다. 이 방법의 효율성을 검증하기 위하여 예제구조물을 해석하여 SAP90의 결과와 비교하였다.

• 생명과학회지
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• 제27권5호
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• pp.524-529
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• 2017

본 연구에서는 zebrafish에 인간의 KCNE1 유전자가 삽입된 형광단백질 vector를 microinjection하고, 그 발현 여부를 확인하고자 하였다. 먼저 양 말단에 제한효소(EcoRΙ, BamHΙ) site를 넣어 제작한 primer들로 genomic DNA에서 KCNE1 유전자를 분리하였다. 그 결과는 약 402 bp 크기의 DNA band였고 이 PCR 산물을 형광단백질 vector인 pPB-CMVp-EF1-GreenPuro 속에 클로닝하여 pPB-CMVp-hKCNE1-EF1-GreenPuro plasmid를 제작하였다. 이렇게 준비된 형광 vector를 zebrafish 수정란에 microinjection하였고, 부화된 치어에서 RT-PCR과 DNA sequencing을 통해 GFP 및 hKCNE1의 발현을 최종 확인하였다. 본 연구는 향후 QT 연장증후군(LQTs)에 대한 동물 모델로써 신경자극 전도, 유전자 치료, 유용 유전자 클로닝을 위한 기술 개발에 응용될 수 있을 것으로 기대된다.

• 약학회지
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• 제49권3호
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• pp.217-224
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• 2005

Human Immunodeficiency Virus type 1 (HIV-l) based lentivirus vector has demonstrated great potential as gene therapy vectors mediating efficient gene delivery and long-term transgene expression in both dividing and nondividing cells. However, for clinical studies it must be confirmed that vector preparations are safe and not contaminated by replication competent lentivirus (RCL) related to the parental pathogenic virus, HIV-l. In this study, we would like to establish the method for titration and RCL detection of lentivirus vector. The titration was determined by vector expression containing the green fluorescent protein, GFP in transduced cells. The titer was $1{\times}10^7$ Transducing Unit/ml in the GFP expression assay and $8.9{\times}10^7$ molecules/ml in the real-time PCR. Also, for the detection of RCL, we have used a combination method of PCR and p24 antigen detection. First, PBS/psi and VSV-G region in the genomic DNA of transduced cells was detected by PCR assay. Second, transfer and expression of the HIV-1 gag gene was detected by p24 ELISA. In an attempt to amplify any RCL, the transduced cells were cultured for 3 weeks (amplification phase) and the supernatant of amplified transduced cell was used for the second transduction to determine whether a true RCL was present (indicator phase). Analysis of cells and supernatant at day 6 in indicator phase were negative for PBS/psi, VSV-G, and p24 antigen. These results suggest that they are not mobilized and therefore there are no RCL in amplification phase. Thus, real-time PCR is a reliable and sensitive method for titration and RCL detection of lentivirus vector.

• 지구물리와물리탐사
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• 제12권1호
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• pp.17-26
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• 2009

향후 발생할 수 있는 자연재해의 기초 자료 확보를 위해 아오가시마섬 지역의 화산 구조를 연구하였다. 아오가시마섬은 일곱개의 섬이 분포하는 이즈열도의 최남단에 위치하고 있는 화산섬으로 효율직인 탐사를 위하여 헬리콥터를 이용한 항공 벡터 자기이상 탐사를 수행하였다. 일반적으로 화산섬의 자기구조를 연구하기 위해서는 총자기이상을 이용하게 되는데 이는 본질적인 오차를 내포하고 있다. 총자기이상은 물리적 특성을 정확히 반영하지 못하기 때문에 맥스웰방정식이나 라플라스 방정식을 만족하지 못하며, 물리적으로 정확한 해석을 수행하기 어려운 단점을 가지고 있다. 또한, 해석을 위하여 한 방향으로 투영된 총자기이상값을 사용하기도 하여 이 과정에서 발생하는 오차 때문에 해석상의 오류가 발생할 수 있다. 이러한 문제점을 보완하기 위하여 이번 연구에서는 벡터 자기이상값을 직접 측정 하였으며, 이를 이용하여 보다 신뢰성 높은 아오가시마섬의 3차원 자기이상 특성을 연구하였다. 이번 연구의 해석결과를 간단히 정리하면, 1A/m 이하의 자화강도를 보이는 지역은 아오가시마섬 남서쪽에 분포하고 있으며, 그 심도는 1-2 km로 해석되었다. 이러한 낮은 자화강도를 보이는 지역은 화산분기 작용의 특성을 고려할 때, 화산분기 작용이 발생했던 지역으로 생각된다.