• The Journal of the Acoustical Society of Korea
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• v.28 no.7
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• pp.646-652
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• 2009

In this paper, welding pitch optimization technique of vehicle subframe is presented considering the fatigue life of spot welding nuggets. Fatigue life of spot welding nuggets is estimated by using the frequency-domain fatigue analysis technique. The input data, which are used in the fatigue analysis, are obtained by performing the dynamic analysis of vehicle model passing through the Belgian road profile and also the modal frequency response analysis of finite element model of vehicle subframe. According to the fatigue life result obtained from the frequency-domain fatigue analysis, the design points to optimize the weld pitch distance are determined. For obtaining the welding pitch combination to maximize the fatigue life of the spot welding nuggets, 4-factor, 3-level orthogonal array experimental design is used. This study shows that the optimized subframe improves the fatigue life of welding nugget with minimum fatigue life about 65.8 % as compared with the baseline design.

• Proceedings of the Korea Information Processing Society Conference
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• 2012.04a
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• pp.1204-1207
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• 2012

본 논문에서는 실행 중인 모듈 프로그램에 새로운 모듈의 삽입 및 제거가 가능한 사용자 수준 모듈 프레임워크(UMF: User-level Module Framework)를 제시한다. 제시한 UMF은 하나의 메인 모듈과 여러 개의 서브 모듈들로 구성되며 서브 모듈은 메인 모듈에 동적으로 삽입 및 제거된다. 제시한 UMF의 타당성을 검토하기 위하여 리눅스 환경에서 GCC 컴파일러의 PIE(Position Independent Executables)옵션을 이용하여 사용자 수준의 메인 모듈과 서브 모듈을 생성하여 동적 삽입 및 제거 기능을 실험한다.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2003.05a
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• pp.262-265
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• 2003

In the present study, subframe was developed using hydroforming technology. The manufacturing process for subframe consists of tube bending, pre-forming and hydroforming. The effects of bending process for manufacturing hydroformed subframe were researched. And the variables of bending process were studied by FEM simulation. The bending method is rotary draw bending that is the most popular, cost-effective bending method for thin walled tubes.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.9C
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• pp.691-696
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• 2008

A new vocoder of Code Excited Linear Predictive (CELP) based on Adaptive Multi Rate (AMR) 7.4kbit/s mode is proposed in this paper. The proposed vocoder achieves a better compression rate in an environment of Speaker Dependent Coding System (SDSC) and is efficiently used for systems, such as OGM(Outgoing message) and TTS(Text To Speech), which needs only one person's speech. In order to enhance the compression rate of a coder, a new Line Spectral Pairs(LSP) code-book is employed by using Centroid Neural Network (CNN) algorithm. In comparison with original(traditional) AMR 7.4 Kbit/s coder, the new coder shows 27% higher compression rate while preserving synthesized speech quality in terms of Mean Opinion Score(MOS).

• Journal of the Institute of Convergence Signal Processing
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• v.17 no.1
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• pp.1-9
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• 2016

In this paper, for the improvement of quality of service(QoS) performance of heterogeneous networks, multi-cell scheduling is proposed. In order to implement the proposed algorithm, for the recognition of the impact on the throughput performance of users, macro-pico-cells that form distributed architecture were proposed. In operating heterogeneous networks, considering the centralized structure, a macro-RRH(Remote Radio Head) deployment scenario was proposed. For interference mitigation of the proposed system, by applying the optional sub-frame, through CQI(Channel Quality Indicator) measurement for each sub-frame period, constraint conditions were measured according to system situations. For the simplification, the pattern of the same ABS muting was assumed. In the above two multi-cell environments, the algorithm of high-speed load balancing maintenance was proposed.

• Proceedings of the Korean Information Science Society Conference
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• 1999.10a
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• pp.584-586
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• 1999

소프트웨어 개발 시 기존 전문가들의 개발 경험을 재사용하는 작업은 개발 기간의 단축 및 비용의 절감의 효과를 가져올 수 있다. 이러한 재사용에 관련된 연구는 소프트웨어공학 분야에서 계속되어 그 하나로 객체지향 프레임워크를 들 수 있다. 객체지향 프레임워크는 검증된 소프트웨어 재사용 부품으로 특정 도메인에 대한 비즈니스 로직을 재사용할 수 있도록 구현된다. 프레임워크 내부에는 재사용되는 로직이 포함되어 있으며 프레임워크 사용자에 의해 커스터마이징 될 모듈을 정의하고 있다. 프레임워크 사용자는 프레임워크를 기반으로 어플리케이션을 개발함으로써 처음부터 개발을 시작하지 않으며 기 개발자들의 경험을 재사용하게 된다. 본 논문에서는 근래 크게 대두되고 있는 가상상점 도메인에 대한 프레임워크를 제시한다. 본 논문에서 제시하는 가사상점 프레임워크는 제인 프레임워크와 주문, 지불, 배달의 3개 서브프레임워크로 구성되며 각각의 프레임워크가 포함한 핫스팟, 제어흐름, 프레임워크 인터페이스를 중심으로 프레임워크의 구성요소 및 설계, 구현에 관한 사항을 기술한다.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.3 no.4
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• pp.7-12
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• 2004

Inspection and analysis are essential process to determine whether a completed product is in given specification or not. Analysis of products with very complicated shape is difficult to carry out direct comparison between inspected coordinate and designed coordinates. So process called as matching or registrations is needed to solve this problem. By defining error between two coordinates and minimizing the error, registration is done. Registration consists of translation, rotation and scale transformations. Error must be defined to express feature of inspected product. In this paper, registration algorithm is developed to determine pose of sub-frame at assembly with body of automobile by defining error between two coordinates considering geometric feature of sub-frame.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.11a
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• pp.155-158
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• 2005

Sub-frame is a key component to damp the vibration of engine-born and isolate the input force from a ground. To enhance the performance of the sub-frame of vehicle, its structure should be designed to be a high performing mechanical filter that exclude the low frequency vibration elements. In this paper, a contribution analysis based on the frequency response function(FRF) is introduced to detect a high sensitive position of the target sub-frame and its results are validated with a SDM(structural dynamic modification) analysis.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.9
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• pp.1633-1637
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• 2008

A protocol is proposed to control the rate of each subcarrier in OFDM-based wireless network systems. The proposed protocol adds an OFDM symbol in CTS frame defined in IEEE 802.11 standard. A receiver determines the rate of its subcarrier after it receives the RTS frame. The determined rate is added to OFDM symbol in CTS frame. In order to synchronize the rate information between the sender and the receiver, error recovery process is proposed. The performance improvement of the proposed method is shown by numerical results.

• Proceedings of the Korea Information Processing Society Conference
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• 2012.11a
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• pp.527-530
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• 2012

비디오 데이터를 효율적으로 검색, 정렬, 탐색, 분류하기 위해서는 프레임 간의 샷 전환 탐지가 선행되어야 한다. 본 논문에서는 디지털 비디오 데이터의 샷 전환 탐지를 위해 비디오 스트림을 구성하고 있는 각 프레임들 간의 화소 밝기 차이와 히스토그램의 변화를 이용하였다. 플래쉬 등과 같은 인위적이고 급격한 화소 밝기변화에 의한 오류를 최소화하기 위해 샷 전환 탐지 이전에 각 프레임 간의 밝기 보상을 적용하였다. 밝기 보정 된 프레임으로부터 프레임의 서브 블록 간의 지역적 화소 밝기 정보, 그리고 프레임의 화소 밝기 값 히스토그램을 비교하여 샷 전환을 탐지한다. 실험에서 제안된 알고리즘은 국가기록원 소장 비디오에 적용하여 효과가 있음을 보였다.