• 대한원격탐사학회지
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• 제26권5호
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• pp.581-591
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• 2010

본 연구에서는 주파수 및 공간 도메인 상에서 선호 분석에 장점이 있는 웨이블릿 기반의 영상 융합 알고리듬을 제안하였다. 개발된 알고리듬은 레이더 영상 신호와 광학 영상 신호의 상대적인 크기를 비교하여 상대적으로 신호 크기가 큰 경우에는 레이더 영상 신호를 융합 영상에 할당하고 크기가 작은 경우에는 레이더 영상 신호와 광학 영상 선호의 가중치 합으로 융합 영상 신호를 결정한다. 사용되는 융합 규칙은 두 영상 신호의 상대적인 신호 비(ratio) 영상 그레디언트, 로컬 영역의 분산 특성을 동시에 고려한다. Ikonos 위성 영상과 TerraSAR-X 위성 영상을 이용한 실험에서 상대적으로 신호 크기가 큰 레이더 신호 만을 융합 영상에 할당하는 기존 방법에 비해 entropy, image clarity, spatial frequency, speckle index 측면에서 우수한 융합 결과를 얻었다.

• 지능정보연구
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• 제18권3호
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• pp.79-96
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• 2012

기술의 발전과 융합이 빠르게 이루어지고 있는 오늘날 유망기술을 어떻게 파악하여, 다양한 후보군들 중에서 최적의 R&D 대상을 어떻게 선정할 것인가에 대한 문제는 주요한 경영의사결정문제 중 하나로 부상하고 있다. 본 연구에서는 이러한 R&D 기술 선정 의사결정을 지원할 수 있는 새로운 지능형 의사결정지원시스템을 제안한다. 본 연구의 의사결정지원시스템은 크게 3가지 모듈로 구성되는데, 우선 첫 번째 모듈인 '기술가치 평가' 모듈에서는 기업이 관심을 갖고 있는 분야의 특허들을 분석하여 유망기술 파악에 요구되는 다양한 차원의 기술가치 평가지수 값들을 산출하는 작업이 이루어진다. 이를 통해, 현재 시점에서의 각 기술의 가치가 다양한 차원에서 평가가 이루어지고 나면, 두 번째 모듈인 '미래기술가치 예측' 모듈에서 이들의 시간 흐름에 따른 변화를 학습한 인공지능 모형을 토대로 각 후보기술들이 미래 시점에 어떤 가치지수값을 갖게 될 것인지 예측값을 산출하게 된다. 마지막 세 번째 모듈인 '최적 R&D 대상기술 선정 지원' 모듈에서는 앞서 두 번째 모듈에서 산출된 각 차원별 예상 가치지수값들을 적절히 가중합하여 기술의 종합적인 미래가치 예측값을 산출하여 의사결정자에게 제공하는 기능을 수행한다. 이를 통해 의사결정자가 자사에 적합한 최적의 R&D 대상기술을 선정할 수 있도록 하였다. 본 연구에서는 제안된 시스템의 적용 가능성을 검증하기 위해, 10년치 특허데이터에 인공신경망 기법을 적용하여 실제 기술가치 예측모형을 구축해 보고, 그 효과를 살펴본다.

• 설비공학논문집
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• 제15권8호
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• pp.652-660
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• 2003

T-history method, measuring heat-of-fusion of phase change material (PCM) in sealed tubes, has the advantages of a simple experimental device and no requirements in sampling process. However, a degree of supercooling used in selecting the range of latent heat release and neglecting sensible heat during the phase change process can cause significant errors in determining the heat of fusion in the original method, which has been improved in order to predict better results by us. In the present study, the modified method was applied to a variety of PCM such as paraffin and lauric acid having very small or no supercooling with a satisfactory precision. Also the selection of inflection point and temperature measurement position was fumed out not to affect the accuracy of heat-of-fusion significantly. As a result, the method can provide an appropriate means to assess a new developed PCM by cycle test even if a very accurate value cannot be obtained.

• 제어로봇시스템학회논문지
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• 제19권2호
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• pp.158-163
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• 2013

The fusion of the GPS (Global Positioning System) and DR (Dead Reckoning) is widely used for position and latitude estimation of vehicles such as a mobile robot, aerial vehicle and marine vehicle. Among the many types of aerial vehicles, grater focus is given on the quad-rotor and accuracy of the position information is becoming more important. In order to exactly estimate the position information, we propose the fusion method of GPS and Gyroscope sensor using the DEKF (Dual Extended Kalman Filter). The DEKF has an advantage of simultaneously estimating state value and a parameter of dynamical system. It can also be used even if state value is not available. In order to analyze the performance of DEKF, the computer simulation for estimating the position, the velocity and the angle in a circle trajectory of quad-rotor was done. As it can be seen from the simulation results using own proposed DEKF instead of EKF on own fusion method in the navigation of a quad-rotor gave better performance values.

• Nuclear Engineering and Technology
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• 제51권7호
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• pp.1860-1865
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• 2019

The confinement degradation of the energetic particles during RMP would be a key issue in success of realizing the successful energy production using fusion plasma, because a 3.5 MeV energetic alpha particle should be able to sustain the burning plasma after the ignition. As KSTAR recent results indicate the generation of high-performance plasma(${\beta}_p{\sim}3$), the confinement of the energetic particles is also an important key aspect in neutral beam driven plasma. In general, the measured absolute value of the neutron intensity is generally used for to estimating the confinement time of energetic particles by comparing it with the theoretical value based on transport calculations. However, the availability of, but for its calculation process, many accurate diagnostic data of plasma parameters such as thermal and incident fast ion density, are essential to the calculation process. In this paper, the time evolution of the neutron signal from an He3 counter during the beam blank has permitted to facilitate the estimation of the slowing down time of energetic particles and the method is applied to investigate the fast ion effect on ELM suppressed KSTAR plasma which is heated by high energy deuterium neutral beams.

• 한국분말재료학회지
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• 제28권2호
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• pp.120-126
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• 2021

In this study, AlSi10Mg alloy powders are synthesized using gas atomization and sieving processes for powder bed fusion (PBF) additive manufacturing. The effect of nozzle diameter (ø = 4.0, 4.5, 5.0 and 8.0 mm) on the gas atomization and sieving size on the properties of the prepared powder are investigated. As the nozzle diameter decreases, the size of the manufactured powder decreases, and the uniformity of the particle size distribution improves. Therefore, the ø 4.0 mm nozzle diameter yields powder with superior properties. Spherically shaped powders can be prepared at a scale suitable for the PBF process with a particle size distribution of 10-45 ㎛. The Hausner ratio value of the powder is measured to be 1.24. In addition, the yield fraction of the powder prepared in this study is 26.6%, which is higher than the previously reported value of 10-15%. These results indicate that the nozzle diameter and the post-sieve process simultaneously influence the shape of the prepared powder as well as the satellite powder on its surface.

• 제어로봇시스템학회논문지
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• 제15권4호
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• pp.365-371
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• 2009

A intelligent mobile hexapod robot with various types of sensors and wireless camera is introduced. We show this mobile robot can detect objects well by combining the results of active sensors and image processing algorithm. First, to detect objects, active sensors such as infrared rays sensors and supersonic waves sensors are employed together and calculates the distance in real time between the object and the robot using sensor's output. The difference between the measured value and calculated value is less than 5%. This paper suggests effective visual detecting system for moving objects with specified color and motion information. The proposed method includes the object extraction and definition process which uses color transformation and AWUPC computation to decide the existence of moving object. We add weighing values to each results from sensors and the camera. Final results are combined to only one value which represents the probability of an object in the limited distance. Sensor fusion technique improves the detection rate at least 7% higher than the technique using individual sensor.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제16권9호
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• pp.2927-2941
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• 2022

The primary task of machine fault diagnosis is to judge whether the current state is normal or damaged, so it is a typical binary classification problem with mutual exclusion. Mutually exclusive events and out-of-domain detection have one thing in common: there are two types of data and no intersection. We proposed a fusion model method to improve the accuracy of machine fault diagnosis, which is based on the mutual exclusivity of events and the commonality of out-of-distribution detection, and finally generalized to all binary classification problems. It is reported that the performance of a convolutional neural network (CNN) will decrease as the recognition type increases, so the variational auto-encoder (VAE) is used as the primary model. Two VAE models are used to train the machine's normal and fault sound data. Two reconstruction probabilities will be obtained during the test. The smaller value is transformed into a correction value of another value according to the mutually exclusive characteristics. Finally, the classification result is obtained according to the fusion algorithm. Filtering normal data features from fault data features is proposed, which shields the interference and makes the fault features more prominent. We confirm that good performance improvements have been achieved in the machine fault detection data set, and the results are better than most mainstream models.

• 대한원격탐사학회지
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• 제35권6_4호
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• pp.1363-1372
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• 2019

본 연구에서는 영상융합 기법을 적용하여 고해상 다분광 영상을 제작할 때 요구되는 융합 파라미터를 분석하고, 하나의 값으로 대표될 수 있는 융합 파라미터를 제시하고자 하였다. 이를 위하여, 한반도 영역을 촬영한 115장의 KOMPSAT-3A 영상을 대상으로 전정색 영상을 모사할 수 있는 선형회귀계수와, 융합영상 제작에 요구되는 융합계수를 분석하였으며, 대표 선형회귀계수와 대표 융합계수를 제시하였다. 대표 융합 파라미터를 사용하여 융합영상을 제작하였을 때, 각 융합영상 간 DN값의 차이가 최적의 융합 파라미터를 사용하였을 때보다 정량적으로 감소함을 확인하였다. 따라서 본 연구는 융합영상 제작에 반영되는 지역적 특성을 최소화할 수 있는 것으로, 융합영상을 하나의 제품 측면에서 제공할 때 활용 가치가 높다.

• Journal of Microbiology and Biotechnology
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• 제20권6호
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• pp.995-1000
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• 2010

A novel deoC gene was identified from Paenibacillus sp. EA001 isolated from soil. The gene had an open reading frame (ORF) of 663 base pairs encoding a protein of 220 amino acids with a molecular mass of 24.5 kDa. The amino acid sequence was 79% identical to that of deoxyribose 5-phosphate aldolase (DERA) from Geobacillus sp. Y412MC10. The deoC gene encoding DERA was cloned into an expression vector and the protein was expressed in Escherichia coli. The recombinant DERA was purified using Ni-NTA affinity chromatography and then characterized. The optimum temperature and pH of the enzyme were $50^{\circ}C$ and 6.0, respectively. The specific activity for the substrate deoxyribose 5-phosphate (DR5P) was $62\;{\mu}mol/min/mg$. The $K_m$ value for DR5P was determined to be 145 mM with the $k_{cat}$ value of $3.2{\times}10^2/s$ from Lineweaver-Burk plots. The EA001 DERA showed stability toward a high concentration of acetaldehyde (100 mM).