• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2004년도 ICEIC The International Conference on Electronics Informations and Communications
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• pp.61-65
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• 2004

An on-chip debugging unit is proposed aiming performance enhancement of JTAG-based SoC systems. The proposed unit comprises a JTAG module and a core breaker. The IEEE 1149.1 standard has been modified and applied to the new JTAG module. The proposed unit eliminates redundant clock cycles included in the TAP command execution stage reducing overall debugging time. TAP execution commands are repeatedly issued to perform debugging of complicated SoC systems. Simulation on the proposed unit shows some $14\%$ performance enhancement and $50\%$ gate count reduction compared to the conventional ones.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회B
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• pp.2352-2356
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• 2008

Heat transfer and performance characteristics have been investigated for a rectangular wavy duct with dimple or protrusion arrays. The test duct was 15mm in height and 105mm wide. The print diameter of the dimple/protrusion wall was 12.99mm and the depth/height of the dimple/protrusion was 3.75mm. Local heat transfer coefficients on the dimple/protrusion wall were measured using a transient TLC technique. The Reynolds number was varied from 3,000 to 10,000. For the wavy duct tested in this study, adverse static pressure characteristics occurred at turning region of the wavy duct due to secondary flows. For the wavy duct with protrusion array, higher heat transfer enhancement level of 7.4 times than smooth straight case in maximum was obtained at low Reynolds number due to the high heat transfer enhancement by vortex flows. Also, the protrusion array increased the performance level of 3.0 at low Reynolds number of 3,000.

• 전자공학회논문지S
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• 제35S권5호
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• pp.111-116
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• 1998

In this paper, we proposed method of performance enhancement of the ultrasonic imaging system using quadrature detector and implementation of the software quandrature detector. Since the quadrature detector is more sensitive than the enbelope detector of the conventional ultrasonic imaging syustem, we are able to achieve the contrast enhnacement. Although hardware quadrature detector is able to process high sped data acquisition, its hardware has complexity. In order to show the performance of the software quadrature we have constructed ultrasonic signal processing system and obtained the reflected signal from the aluminum specimen using A/D convertor. Our experimental results showed that image of the quadrature detector is better than that of the envelope detector.

• 한국정보통신설비학회:학술대회논문집
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• 한국정보통신설비학회 2008년도 정보통신설비 학술대회
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• pp.69-72
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• 2008

u-City 도시통합운영 플랫폼은 u-City 내 교통, 건물, 시설물 등의 첨단화된 기반 시설을 전반적으로 관리하고 체계적으로 통제 가능하도록 한다. 그러나, 도시통합운영 플랫폼에 인가되는 부하는 도시 전반에 분산된 센서와 같은 정보원의 규모뿐 아니라 그 정보의 복잡성에도 의존할 수 밖에 없어, 효율적인 도시운영을 위해서는 플랫폼의 성능확보 방안이 고려되어야 한다. 일반적인 성능개선의 방법으로는 이미 발생한 부하의 효율적 처리를 통한 개선과 더불어 부하원의 근본적 통제와 같은 우회적 방법이 사용될 수 있다. 본 고에서는 네트워크 구조 개선을 통한 부하분산 방법과 더불어 플랫폼의 주 부하원인 센서 네트워크와의 연동방식 개선이라는 두 가지 측면에서 u-City 도시통합운영 플랫폼의 성능개선 방향을 고찰한다.

• 국제지역연구
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• 제20권1호
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• pp.209-234
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• 2016

This study examines the effects of exporter agglomeration on purely local firms' decision to undertake internationalization and the resultant performance enhancement from internationalization using propensity score matching and difference-in-differences approach. We find that the likelihood of starting to export is higher when purely local firms are located in a region with a higher level of exporter agglomeration, as positive externalities allow them to overcome insufficient internal resources and reduce the large initial foreign market entry costs. We also find that newly exporting firms are more likely to experience greater performance enhancement from exporting when they are locate in a region with a lower level of exporter agglomeration.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2011년도 제36회 춘계학술대회논문집
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• pp.12-15
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• 2011

현재 가장 널리 쓰이고 있는 케로신-액체산소 액체로켓엔진은 신뢰도와 개발 비용의 문제로 이전의 설계에서 크게 벗어나지 않은 스킴을 사용하고 있다. 하지만 냉각 방법, 엔진 싸이클 및 냉각유로 형상의 변경, 추진제가 아닌 추가의 냉각제 이용 등의 여러 방법으로 효율을 향상시킬 수 있다. 여기에서는 그 중 냉각제를 케로신에서 액체산소로 변경하여 효율이 높아진 사례에 대하여 기술한다.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2008년도 춘계종합학술대회 A
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• pp.784-788
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• 2008

In this research, we propose a remote speech input unit, a new method of user-friendly speech input in speech recognition system. We focused the user friendliness on hands-free and microphone independence in speech recognition applications. Our module adopts two algorithms, the automatic speech detection and speech enhancement based on the microphone array-based beamforming method. In the performance evaluation of speech detection, within-200msec accuracy with respect to the manually detected positions is about 97percent under the noise environments of 25dB of the SNR. The microphone array-based speech enhancement using the delay-and-sum beamforming algorithm shows about 6dB of maximum SNR gain over a single microphone and more than 12% of error reduction rate in speech recognition.

• The Journal of the Acoustical Society of Korea
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• 제23권4E호
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• pp.125-133
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• 2004

In this paper, we propose a critical banded wavelet packet-based spectral subtraction for speech enhancement. Critical banded wavelet packet, which reflects the human auditory system, may lead to minimization of intelligibility loss and quality improvement of the enhanced speech in the spectral domain, when combined with an appropriate spectral subtraction gain function. The proposed method shows better performance than the conventional one in comparative assessments. We also show that, for effective evaluation of enhanced speech, it is essential to consider the characteristics of speech quality measures.

• 한국멀티미디어학회논문지
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• 제21권2호
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• pp.108-116
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• 2018

In this paper, we propose an image enhancement method based on Multi-Scale Retinex theory that designs Unsharp Masking Filter (UMF) and emphasizes the contrast ratio adaptively. Unsharp Masking (UM) technique emphasizes image sharpness and improves contrast ratio by adding high frequency component to the original image. The high frequency component is obtained by differentiating between original image and low frequency image. In this paper, we present how to design an UMF kernel and to adaptively apply it to increase the contrast ratio according to multi-scale retinex theory which resembles human visual system. Experimental results show that the proposed method has better quantitative performance indexes such as PSNR, ambe & SSIM and better qualitative feature like halo artifact suppression.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2005년도 추계 학술대회논문집
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• pp.245-248
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• 2005

SCRamjet is the key technology for hypersonic flight over mach number 6. It is characterized by very short residence time in combustor because its internal flow is supersonic. In this short time, the whole process of combustion must be done. Especially numerical study of combustor is important because air-fuel mixing rate influences the performance of combustor. Various methods of air-fuel mixing enhancement are proposed. Among these, cavity injection method is selected to study in this paper. The numerical study is conducted with the variation of the cavity length at the fixed height of unit and jet injection on the downstream of cavity.