• 반도체디스플레이기술학회지
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• 제6권4호
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• pp.43-47
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• 2007

In this paper, we propose a novel sensor system for measuring the arterial pulse in an oral cavity. In order to measure pulse wave in oral cavity, the proposed system is designed with reflection type arterial wave sensor, not by using transmission type arterial pulse wave sensor. Driving circuit through pulse current is designed for solving self-heating problem of LED. The effectiveness of the proposed sensor system is compared with pulse wave between pulse wave of oral cavity and other body parts as well as with characteristic measurements. The experiment shows that the proposed sensor system is adaptive to capturing consecutive and meaningful biometric signals through the variation of pulse wave changes in oral cavity when exercising. The study result expects to design and develop mobile sensors which could be adapted to healthcare devices.

• 한국방송∙미디어공학회:학술대회논문집
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• 한국방송공학회 2008년도 추계학술대회
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• pp.157-160
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• 2008

본 논문에서는 Raptor 코드를 이용하여 계층화 비디오를 적응적으로 전송하는 방법을 보여 준다. 클라이언트는 정보를 수신 할 뿐만 아니라 수신한 정보를 다른 클라이언트와 교환함으로서 서버 의존도를 줄여 손실 상황에 대한 강인함을 지니게 된다. Raptor code의 특징을 이용하여 peer-to-peer 환경에서 효율적인 비디오 전송이 가능하다. 이러한 방법을 이용하여 실시간 UCC 비디오와 같은 콘텐츠를 자원이 제한적인 환경에서도 효율적으로 전송 할 수 있는 방법을 보인다.

• 전자공학회논문지B
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• 제33B권3호
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• pp.126-132
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• 1996

In this paper, the complexity reduction method for QCELP speech coder (IS-96) without any perfomrance degradation is proposed for the vecoder of CDMA digital cellular system. The energy terms in pitch parameter search and codebook search routines that require large computations are calculated recursively by utilizing the overlapped structure of code vectors in adaptive codebook and excitation codebook. The additional complexity reduction in the codebook search routine can be achieved by using a simple form in calculation of the energy term when the initial codebook value is zero. In the case of lower transmission rates such as 4,2,1 kbps, the complexity reduction by recursive calulations of energy term is increased.

• 한국공작기계학회논문집
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• 제12권2호
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• pp.1-8
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• 2003

Conventionally used linear or circular interpolator is undesirable for the precision machining of 3D free-form surface as the following reason: the transmission errors due to the huge number of data, discontinuity of segmentation, unsmooth motion speed. To this regard, modern CNC machine tools are designed with the function of machining arbitrary parametric curves. However, these systems don't consider the adaptive federate, which dominates the quality of the machining process. This paper proposes a NURBS interpolator for the constant material removal rate. That is accomplished by the variable federate using curvature of curve. The curvature-compensated feederate system has important Potential applications in ensuring part accuracy and protecting cutting tool. The simulated result show it can be applicable to the real machining.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제5권7호
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• pp.1293-1310
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• 2011

A simple modification of well known Low Energy Adaptive Clustering Hierarchy (LEACH) protocol is proposed to exploit cooperative diversity. Instead of selecting a single cluster-head, we propose M cluster-heads in each cluster to obtain a diversity of order M. The cluster-heads gather data from all the sensor nodes within the cluster using same technique as LEACH. Cluster-heads transmit gathered data cooperatively towards the destination or higher order cluster-head. We propose a code combining based cooperative diversity protocol which is similar to coded cooperation that maximizes the performance of the proposed cooperative LEACH protocol. The implementation of the proposed cooperative strategy is analyzed. We develop the upper bounds on bit error rate (BER) and frame error rate (FER) for our proposal. Space time block codes (STBC) are also a suitable candidate for our proposal. In this paper, we argue that the STBC performs worse than the code combining cooperation.

• 한국정보보호학회:학술대회논문집
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• 한국정보보호학회 2006년도 하계학술대회
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• pp.295-298
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• 2006

인터넷의 발달로 네트워크를 통한 멀티미디어 데이터 서비스가 늘어나면서 유료 콘텐츠에 대한 저작권 관리와 보호 및 다양한 이기종의 단말 장치에 적합한 콘텐츠 적응(adaptation) 서비스에 대한 필요성이 높아지고 있다. 이를 위하여 현재까지 DRM, Scalable Coding, Progressive Encryption, ISMA, ARMS, Metadata Adaptation 등 다양한 연구가 진행되어 왔지만 요구사항을 포괄적으로 만족하는 멀티미디어 전송 프레임워크는 부재한 상태이다. 이에, 본 논문에서는 기존 기법을 분석하고 기능을 통합하여 안전하고 보다 여러 종류의 단말 장치에 서비스가 가능하며 다양한 서비스 형태를 가질 수 있는 프레임워크를 설계하였다. 이를 통해 멀티미디어 서비스가 보다 광범위하게 활용되고 확산 될 수 있으리라 기대된다.

• Journal of information and communication convergence engineering
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• 제6권4호
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• pp.421-424
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• 2008

In torque transmission system, we must suppressed vibration for Accuracy characteristic response of motor, Therefore, vibration suppression factor is very important motor control. To suppress vibration, a various control method has been proposed. Specially, one method of vibration suppression used disturbance observer filter. This method is torsion torque passing disturbance observer filter. By the estimated torsion torque feedback, vibration can be suppressed. The CDM(coefficient diagram method) is used to design the filter and Proportional controller. But using coefficient diagram method, not adapted controller parameter in disturbance. For this solution, we used fuzzy controller for auto tuning controller parameter. We proved this approach is confirmed by simulation.

• Journal of information and communication convergence engineering
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• 제9권5호
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• pp.591-596
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• 2011

Image denoising is a key issue in all image processing researches. Generally, the quality of an image could be corrupted by a lot of noise due to the undesired conditions of image acquisition phase or during the transmission. Many approaches to image restoration are aimed at removing either Gaussian or impulse noise. Nevertheless, it is possible to find them operating on the same image, which is called mixed noise and it produces a hard damage. In this paper, we proposed noise type classification method and a mixed nonlinear filter for mixed noise suppression. The proposed filtering scheme applies a modified adaptive switching median filter to impulse noise suppression and an efficient nonlinear filer was carried out to remove Gaussian noise. The simulation results based on Matlab show that the proposed method can remove mixed Gaussian and impulse noise efficiently and it can preserve the integrity of edge and keep the detailed information.

• Journal of information and communication convergence engineering
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• 제14권2호
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• pp.78-83
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• 2016

In underwater acoustic communication, the transmitted signals are severely influenced by the reflections from both the sea surface and the sea bottom. As very large reflection signals from these boundaries cause an inter-symbol interference (ISI) effect, the communication quality worsens. A channel estimation-based equalizer is usually adopted to compensate for the reflected signals under the acoustic communication channel. In this study, a feed-forward equalizer (FFE) with the least mean squares (LMS) algorithm was applied to a quadrature phase-shift keying (QPSK) transmission system. Two different types of equalizers were adopted in the QPSK system, namely a real-coefficient equalizer and a complex-coefficient equalizer. The performance of the complex-coefficient equalizer was better than that of two real-coefficient equalizers. Therefore, a Hilbert transform was applied to the real-coefficient binary phase-shift keying (BPSK) system to obtain a complex-coefficient BPSK system. Consequently, we obtained better results than those of a real-coefficient equalizer.

• 한국정보과학회:학술대회논문집
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• 한국정보과학회 2004년도 봄 학술발표논문집 Vol.31 No.1 (A)
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• pp.691-693
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• 2004

Mobile Ad hoc network은 stationary infrastructure의 도움 없이 이동 노드들이 필요 시 multi-hop wireless links network 형태를 구성하여 통신이 이루어지게 하는 network이다. 따라서 효율적인 라우팅 프로토콜의 개발이 중요한 issue인데 최근에는 routing overhead가 적은 on-demand 프로토콜이 주목을 받고 있다. On-demand 프로토콜은 새로운 route을 구성하기 위해서 query packet을 broadcasting하게 되는데, 특히 노드들의 mobility가 많은 mobile ad hoc network(MANET)의 경우에는 더욱더 자주 발생하게 되는데, blind broadcasting은 neighbor 노드들 간의 radio transmission region overlap에 의해 redundancy, contention, collision 같은 broadcast storm 문제를 발생시키게 된다. 본 논문은 on-demand 프로토콜의 broadcast storm 문제를 해결하기 위해 Neighbor Topology을 고려 한 Dynamic Adaptation Query flooding scheme을 제시한다. 또한 Dynamic Adaptive Query flooding scheme은 broadcast storm 문제 해결뿐만 아니라 network의 congestion을 감소시켜 data packet의 성능 향상에도 기여 할 것이다.