• 말소리와 음성과학
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• 제6권4호
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• pp.91-99
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• 2014

Speaking styles tend to have an influence on spectral characteristics of produced speech. There are not many studies on the spectral characteristics of speech because of complicated processing of too much spectral data. The purpose of this study was to examine spectral characteristics and formant bandwidths of English vowels produced by nine American males with different speaking styles: clear or conversational styles; high- or low-pitched voices. Praat was used to collect pitch-corrected long-term averaged spectra and bandwidths of the first two formants of eleven vowels in the speaking styles. Results showed that the spectral characteristics of the vowels varied systematically according to the speaking styles. The clear speech showed higher spectral energy of the vowels than that of the conversational speech while the high-pitched voice did the same over the low-pitched voice. In addition, front and back vowel groups showed different spectral characteristics. Secondly, there was no statistically significant difference between B1 and B2 in the speaking styles. B1 was generally lower than B2 when reflecting the source spectrum and radiation effect. However, there was a statistically significant difference in B2 between the front and back vowel groups. The author concluded that spectral characteristics reflect speaking styles systematically while bandwidths measured at a few formant frequency points do not reveal style differences properly. Further studies would be desirable to examine how people would evaluate different sets of synthetic vowels with spectral characteristics or with bandwidths modified.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2006년도 춘계학술대회 논문집
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• pp.7-14
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• 2006

Detection and identification of targets from remotely sensed imagery are of great interest for civilian and military application. This paper presents an algorithm for target detection in high spatial resolution imagery based on the spectral and the dimensional characteristics of the reference target. In this algorithm, the spectral and the dimensional information of the reference target is extracted automatically from the sample image of the reference target. Then in the entire image, the candidate target pixels are extracted based on the spectral characteristics of the reference target. Finally, groups of candidate pixels which form isolated spatial objects of similar size to that of the reference target are extracted as detected targets. The experimental test results showed that even though the algorithm detected spatial objects which has different shape as targets if the spectral and the dimensional characteristics are similar to that of the reference target, it could detect 97.5% of the targets in the image. Using hyperspectral image and utilizing the shape information are expected to increase the performance of the proposed algorithm.

• 대한원격탐사학회지
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• 제22권1호
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• pp.41-47
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• 2006

Detection and identification of targets from remotely sensed imagery are of great interest for civilian and military application. This paper presents an algorithm for target detection in high spatial resolution imagery based on the spectral and the dimensional characteristics of the reference target. In this algorithm, the spectral and the dimensional information of the reference target is extracted automatically from the sample image of the reference target. Then in the entire image, the candidate target pixels are extracted based on the spectral characteristics of the reference target. Finally, groups of candidate pixels which form isolated spatial objects of similar size to that of the reference target are extracted as detected targets. The experimental test results showed that even though the algorithm detected spatial objects which has different shape as targets if the spectral and the dimensional characteristics are similar to that of the reference target, it could detect 97.5% of the targets in the image. Using hyperspectral image and utilizing the shape information are expected to increase the performance of the proposed algorithm.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2008년도 International Symposium on Remote Sensing
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• pp.243-246
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• 2008

The Compact Airborne Imaging Spectrometer System (CAISS) was jointly designed and developed as the hyperspectral imaging system by Korea Aerospace Research Institute (KARI) and ELOP inc., Israel. The primary mission of the CAISS is to acquire and provide full contiguous spectral information with high quality spectral and high spatial resolution for advanced applications in the field of remote sensing. The CAISS consists of six physical units; the camera system, the gyro-stabilized mount, the jig, the GPS/INS, the power inverter and distributor, and the operating system. These subsystems shall be tested and verified in the laboratory before the flight. Especially the camera system of the CAISS shall be calibrated and validated with the calibration equipments such as the integrated sphere and spectral lamps. To improve data quality and availability, it is the most important to understand the mechanism of hyperspectral imaging system and the radiometric and spectral characteristics. This paper presents the major characteristics of camera system on the CAISS and summarizes the results of radiometric and spectral experiment during preliminary system verification.

• 한국전기전자재료학회논문지
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• 제22권12호
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• pp.1058-1062
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• 2009

For the investigation of the mechanism of photoelectric characteristics of a hydrogenated amorphous silicon thin film transistor(a-Si:H TFT), spectral characteristics of various backlights were analyzed in terms of the photon energy at each wavelength. Photon energy spectral characteristics were obtained through the multiplication of each photon energy and spectral intensities of backlights at each wavelength and the total photon energies were obtained by the integration of the photon energy spectrums. From the comparison of the experimental photo leakage current and the calculated photon energy, it was possible to conclude that the absorption of illuminated backlight to a-Si:H layer and the generation of electrons and holes are mainly carried out at the wavelength less than 500 nm as described in previous reports.

• Journal of Mechanical Science and Technology
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• 제18권3호
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• pp.395-406
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• 2004

The spectral element model is known to provide very accurate structural dynamic characteristics, while reducing the number of degree-of-freedom to resolve the computational and cost problems. Thus, the spectral element model for an axially moving Bernoulli-Euler beam subjected to axial tension is developed in the present paper. The high accuracy of the spectral element model is then verified by comparing its solutions with the conventional finite element solutions and exact analytical solutions. The effects of the moving speed and axial tension on the vibration characteristics, wave characteristics, and the static and dynamic stabilities of a moving beam are investigated.

• 한국측량학회지
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• 제32권3호
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• pp.185-190
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• 2014

The purpose of this research is to extract spectral reflectance characteristics of concretes through basic experiment on concrete specimens and site experiment on actual concrete structures using a field portable spectrometer and a VNIR hyperspectral sensor. A spectrometer (GER-3700) and a VNIR hyperspectral camera (AisaEagle VNIR Hyperspectral Camera) were utilized for extracting spectral characteristics of concrete specimens. Concretes normally show similar patterns that have correlation above 80%, while the high-strengthened concretes display very different results from the normal-strength concretes. We also made a certain conclusion in the laboratory experiment on concrete specimens that both the spectrometer and the VNIR camera vary in spectral reflectance depending on concrete strengths.

• 한국광학회지
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• 제6권4호
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• pp.266-273
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• 1995

칼라영상센서의 분광감응 특성은 칼라영상의 색을 결정하는 중요한 요인이 된다. 칼라영상센서의 분광특성을 간편하게 측정할 수 있는 장치를 제작하고 이를 사용하여 CCD 칼라 카메라의 분광특성을 조사하였다. 측정장치는 가시광선 영역내에서 단색광의 파장뿐만아니라 세기도 간편하게 조절할 수 있도록 제작된 광학부와 칼라영상센서의 출력신호를 디지탈값으로 처리하여 나타내는 색분석부로 구성되었다. 광학부에서 만들어진 단색광들에 대한 카메라의 출력값 R, G, B를 측정하였으며 이로부터 카메라의 연색성 및 선형성을 평가하였다. 이로써 제작된 측정장치가 칼라영상센서의 분광특성 측정 및 성능평가에 매우 유용함을 확인할 수 있었다.

• ETRI Journal
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• 제31권3호
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• pp.292-297
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• 2009

The power spectral density of a signal can be estimated most accurately by using a window with a narrow bandwidth and large sidelobe attenuation. Conventional windows generally control these characteristics by only one parameter, so there is a trade-off problem: if the bandwidth is reduced, the sidelobe attenuation is also reduced. To overcome this problem, we propose using a Butterworth window with two control parameters for power spectral density estimation and analyze its characteristics. Simulation results demonstrate that the sidelobe attenuation and the 3 dB bandwidth can be controlled independently. Thus, the trade-off problem between resolution and spectral leakage in the estimated power spectral density can be overcome.

• 한국소음진동공학회논문집
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• 제16권4호
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• pp.387-393
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• 2006

이 논문에서는 내부에 비정상 유동이 흐르는 균일한 직선 파이프에 대한 스펙트럴요소모델을 개발하였다. 개발된 스펙트럴요소모델에 대한 스펙트럴요소행렬은 주파수 영역에서 구한 파이프 역학 방정식의 엄밀해를 이용하여 유도되었다. 이 스펙트럴요소모델의 정확성을 평가하고 한 예제 파이프 계의 진동특성과 파이프 내부 유동특성을 고찰하기 위하여 스펙트럴 동역학 해석을 수행하였다.