• Journal of the Earthquake Engineering Society of Korea
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• v.10 no.5 s.51
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• pp.99-106
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• 2006

The Real-Time Hybrid Test system presented in this paper is based on the pseudodynamic test method, and it combines physical testing with model-based simulation. The system is designed to achieve a rate of loading that is significantly higher than that of a conventional pseudodynamic test approaching the real-time response of a structure subjected to earthquake loads. To provide robust computation environment for the analysis of many degree-of-freedom structures, the system adopts an implicit time integration scheme in the model-based simulation. This paper presents an overview of the developed system and numerical simulations that were conducted to evaluate the performance of the computation scheme adopted here. Results of these studies have demonstrated the good performance of the computation scheme for real-time multiple-degree-of-freedom tests.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.45 no.1
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• pp.21-29
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• 2017

In this paper, the total procedure for composite laminate mechanical joint (ASTM D5961 Proc. A, B) from fixture design to test analysis was showed. Composite laminate mechanical joints were analyzed using the FEM(Finite Element Method) and compared to test results. A progressive failure analysis was applied to FEM to analyze the failure behavior of test specimens. Three failure theories - maximum stress, maximum strain, and Tsai-Wu were applied to FEM to predict test failure load. General parameters for composite laminate joints were reviewed and the differences of bearing strength were compared with major parameters.

• Applied Chemistry for Engineering
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• v.10 no.7
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• pp.1066-1072
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• 1999

The physical properties of polymer concrete were investigated for development of high-performance construction materials. Various specimens of polymer concrete were prepared using unsaturated polyester resin as the polymer-binder with the various dosage of calcium carbonate as microfiller (5~20 wt %) and fine aggregate(10~50 wt %). For the evaluation of the physical properties of polymer concretes, tests such as compressive strength, flexural strength, water absorption test, hot water immersion test, acid resistance test and pore size distribution analysis were conducted. As a result, it is concluded that compressive and flexural strengths of polymer concretes increased up to 4 times than those of conventional cement concrete. Whereas the compressive and flexural strengths of polymer concretes tested after hot water immersion, compared with those of polymer concretes tested before hot water immersion, decreased about 67%, 47%, respectively. By hot water immersion, total pore volume and porosity(%) of polymer concretes were remarkable increased due to decomposition of polymer binder. And also, it is showed that water absorption(%) and weight loss(%) of polymer concrete specimens by acid immersion, compared with those of ordinary portland cement concrete, decreased about 1/100, 1/27, respectively.

• Journal of Technologic Dentistry
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• v.35 no.1
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• pp.43-48
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• 2013

Purpose: This study aimed to investigate the shear bond strength for non-precious alloy castings without beryllium, which has been used repeatedly for economical reason. Methods: The Schmitz-Schulmeyer test method was used to evaluate the shear bond strength between the non-beryllium Ni-Cr alloy Vera Bond 2V(AlbaDent, Inc. USA) and the Ceramco 3(Dentstply, York, PA, USA) porcelain powder. The maximum loading and shear bond strength were measured. The average shear strength(MPa) was analyzed with the one-way ANOVA and the Tukey's test( =.05). The fracture specimens were examined using Microscope to determine the failure pattern. Results: The mean shear bond strengths(SD) in MPa were group A(100% new metal) control 28.72(3.31); group B(50% new + 50% reused) 27.28(1.13); group C(all reused) 26.61(5.47). Microscope examination showed that group A and B specimens presented mixed failure, and group C specimens showed adhesive failure. Conclusion: In conclusion, forward this non-precious alloy dose not contain beryllium for how should use a more systematic study and for future advanced research is performed giving effect to be considered desirable.

• Journal of the Korean Society for Nondestructive Testing
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• v.22 no.4
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• pp.402-410
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• 2002

Recently the necessity of study on optical measuring method using laser to detect the pipeline's defect in nuclear facilities, chemical industries and power plants has been increased. Because laser light can be delivered to a remote area without any difficulties, the application of laser in many industries can solve several difficulties from the limitation of access in danger area and reduce the risks of workers. Therefore, we applied a new experimental technique to the measurement of internal defects in pressure vessels with the combination of shearography and image processing technique and detected the internal cracks of pressure vessels in the former paper. In this paper, we used the same optical system as in the former study and found the optimum shearing magnitude by comparing the real length of specimen with experimental results. A variety of conditions were applied to certify the validity of this method. Actually, several specimens which have different lengths and depths were used in this experiment under the three diverse pressure. Consequently, we have carried out this experiment to determine the limit of measurement ability with analyzing errors.

• Journal of KIISE:Software and Applications
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• v.37 no.9
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• pp.712-721
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• 2010

This paper proposes a new fire-flame detection method using probabilistic membership function of visual features and Fuzzy Finite Automata (FFA). First, moving regions are detected by analyzing the background subtraction and candidate flame regions then identified by applying flame color models. Since flame regions generally have continuous and an irregular pattern continuously, membership functions of variance of intensity, wavelet energy and motion orientation are generated and applied to FFA. Since FFA combines the capabilities of automata with fuzzy logic, it not only provides a systemic approach to handle uncertainty in computational systems, but also can handle continuous spaces. The proposed algorithm is successfully applied to various fire videos and shows a better detection performance when compared with other methods.

• Applied Biological Chemistry
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• v.40 no.4
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• pp.301-306
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• 1997

This study is presented to investigate the physico-chemical properties and qualities for the starch isogenic lines bred in barley(Hordeum vulgare L.).The pearling yield showed higher value in Franubet and Wafranubet than others, but the whiteness of pearled barley varied with the cultivars. The milling rate showed excellence in Franubet, fractured granular lines, whereas that of the waxy and round endosperm isogenic lines is poor. Franubet, the lines having fractures starch granule, was highest in starch content. The highest value in swelling power and water-binding capacity of the barley was proved by the lines having waxy and fractured starch endosperms. The amylogram patterns indicated that the waxy lines such as Wanubet and Wafranubet have lower initial gelatinization temperature and higher maximum viscosity than those of the normal lines. ${\beta}-Glucan\;viscosity$ was generally higher in waxy barley but changed greatly with the cultivars. The water absorption, soluble solid and expansibility in cooking property showed the highest value in waxy and fractured starch granular lines, and the whiteness of cooked barley did not differ with cultivars.

• 한국HCI학회:학술대회논문집
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• 2007.02a
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• pp.143-149
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• 2007

영상은 동적인 시각 이미지와 청각의 결합에 의해 감성적인 반응을 유도한다. 다양한 영상 기법을 통하여 감성적 반응의 극대화를 추구하는 영화는 영상의 시청각적 요소들을 감성의 관점에서 효과적으로 설계하는데 본보기가 된다. 그러나, 제품의 설계속성들에 대한 감성적 평가결과를 모형화하는 감성공학적 관점에서 볼 때 영화는 시청각적 자극의 수준이 극히 다양하고 동적인 경험재로 모형화의 어려움이 있다. 본 연구에서는 영화의 감성 모형을 구축하기 위한 사전연구의 단계로 영화에서의 시청각적 요인들을 문헌조사를 통해 수집, 정리, 선별하고 이러한 시청각적 요인들 중에 영화를 관람하는 관객의 감성적, 인지적 반응에 영향을 주는 유효한 요인들을 객관적이고 체계적으로 탐색하고자 하였다. 이를 위해, 감성 및 인지적 반응의 변화를 생체신호를 통해 측정하는 한편, 생체신호의 측정 시 사용된 영화의 시청각적 자극요인을 Video/Audio Processing방법에 의해 연속적인 수치로 정량화하였다. 생체신호와 정량화된 시청각적 자극요인을 동기화하고 통계적으로 분석함으로써, 생체신호의 반응과 시청각적 자극요인과의 인과관계를 통계적으로 신뢰성있는 수준에서 검증하고자 하였다. 생체신호를 종속변수로, 시청각적 자극요인을 독립변수로 하는 896개의 부분선형회귀모형(Partial Linear Regression Model)들 중 통계적으로 유의한 선형관계에 있는 경우의 빈도분석에 의하면, 시각적 요인들 중에는 밝기(Brightness), 대비(Contrast), 색상(Color), 움직임(Motion), 장면전환속도(Shot change Rate), 주요대상의 상대적 크기가, 청각적 요인들 중에는 Peak주파수, Peak주파수의 음량, 평균음량, 소음비(Sound-to-Noise Ratio)가 생체신호의 변화에 통계적으로 유의한 영향을 주는 것으로 나타났다. 이는, 위의 시청각적 자극 요인들은 특히 관객의 감성 및 인지적인 반응에 유의한 영향을 주는 요소로 작용할 수 있음을 시사하고 있다. 이를 토대로, 위의 시청각적 자극 요인들이 가지는 다양한 조합들을 설명변수로 하는 통계적인 영화의 감성 모형을 구축할 수 있을 것으로 기대한다.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.45 no.9
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• pp.711-723
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• 2017

This paper proposes a flight control system for an organic flight array(OFA) which has a new configuration to consist of multi modularized ducted-fan unmanned aerial vehicles (UAVs). The OFA is able to apply to various missions such as indoor reconnaissance, communication relay, and radar jamming by using capability of hover flight. The OFA has a distinguished advantage due to reconfigurable structure to assemble or separate with respect to its missions or operational conditions. A dynamic modelling of the OFA is derived based on equations of motion of the single ducted-fan modules. In order to apply nonlinear control method, an affine system of attitude dynamics is derived. Moreover, the control system is composed of a back-stepping controller for attitude control and a PID controller for position control. Then the performance of the proposed controller is verified via a numerical simulation under wind disturbance.

• The Journal of the Acoustical Society of Korea
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• v.19 no.3
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• pp.26-34
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• 2000

In this paper, we propose a 4kbps speech coder that combines the harmonic vector excitation coding with time-separated transition coding. The harmonic vector excitation coding uses the harmonic excitation coding in the voiced frame and uses the vector excitation coding with the structure of analysis-by-synthesis in the unvoiced frame, respectively. But two mode coding method is not effective for transition frame mixed in voiced and unvoiced signal and a new method beyond using unvoiced/voiced mode coding is needed. Thus, we designed a time-separated transition coding method for transition frame in which a voiced/unvoiced decision algorithm separates unvoiced and voiced duration in a frame, and harmonic-harmonic excitation coding and vector-harmonic excitation coding method is selectively used depending on the previous frame U/V decision. In the decoder, the voiced excitation signals are generated efficiently through the inverse FFT of harmonic magnitudes and the unvoiced excitation signals are made by the inverse vector quantization. The reconstructed speech signal are synthesized by the Overlap/Add method.