• 한국주거학회:학술대회논문집
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• 한국주거학회 2009년도 추계학술발표대회 논문집
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• pp.213-216
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• 2009

The purpose of this study is analyzing temporal flow about 20 detailed performance items in the "Housing Performance Grading Indication System". This study try to figure out situations according grade in detailed performance item and to analyze change item about 112 cases(2 cases in 2006, 15 cases in 2007, 46 cases in 2008, 49 cases in 2009), from January 9, 2006 which system is undertaken, to October, 2009. This system consists of 5 main performance section, 14 performance categories and 20 detailed performance items. 5 main performance parts are Noise and Acoustics(Light-weight impact sound control, heavy-weight impact sound control, sound control of toilet, sound control of party wall), Long-life(flexibility, remodeling & maintenance, durability), Landscape & Indoor Environment(landscape, formaldehyde control & ventilation, daylighting, thermal environment), Welfare & Barrier-free(playground and community center, welfare space, barrier-free design), Fire Safety(fire safety, safe place, fire-resisting quality). Total efficiency about housing can understand systematically of 20 perfomance items though this research.

• 방송공학회논문지
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• 제9권1호
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• pp.9-16
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• 2004

본 논문에서는 차량용 음성명령어기의 사용을 위한 전처리 과정으로 음성개선 방법을 다룬다 특히 보다 주위 소음에 자유롭고 단말 조작에 있어 안정성을 보장하기 위하여 일반적 단일 마이크로폰으로 처리되는 잡음뿐만 아니라 음성명령어를 제외한 오디오 신호 등 비정적 통계적 특성을 갖는 소음들도 제거 될 수 있도록 음성개선 방법을 제안한다. 우리는 2개의 마이크로폰을 가지고 BSS 알고리즘을 적용하여 비정적 신호들을 분리하고, 분리된 신호에 대하여 Kalman 필터를 이용하여 시간상 단구간 정적 잡음을 제거한다. 인식 실험 결과를 통하여 공간적, 시간적 음성개선 방법이 순차적으로 적용될 때, 실제 차량 환경에서 음성 개선 알고리즘으로 적용될 수 있음을 보였다.

• 한국통신학회논문지
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• 제37A권11호
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• pp.961-971
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• 2012

This article is concerned with effective numerical techniques for partial differential equation (PDE)-based image restoration. Numerical realizations of most PDE-based denoising models show a common drawback: loss of fine structures. In order to overcome the drawback, the article introduces a new time-stepping procedure, called the method of nonflat time evolution (MONTE), in which the timestep size is determined based on local image characteristics such as the curvature or the diffusion magnitude. The MONTE provides PDE-based restoration models with an effective mechanism for the equalization of the net diffusion over a wide range of image frequency components. It can be easily applied to diverse evolutionary PDE-based restoration models and their spatial and temporal discretizations. It has been numerically verified that the MONTE results in a significant reduction in numerical dissipation and preserves fine structures such as edges and textures satisfactorily, while it removes the noise with an improved efficiency. Various numerical results are shown to confirm the claim.

• 방송공학회논문지
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• 제6권2호
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• pp.160-168
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• 2001

본 논문에서는 동영상 정보를 파노라마로 합성하는 자동화된 알고리즘을 제안한다. 제안한 카메라 모델은 일반화된 파노라마 영상의 특성을 반영하며, 기존의 방법과는 달리 영상의 확대 및 축소를 고려하여 보다 개선된 파노라마 합성 영상을 제공한다. 또 한 통계적 특성을 이용하여 움직이는 물체 또는 기타 여러 잘음(nolle)의 영향을 배제하는 전역 움직임 추정 기법을 사용하여 기존 방법의 문제점을 보완한다. 이를 통해 파노라마 영상으로부터 움직이는 물체 또는 잡음을 제거하여 더 깨끗하고 완벽한 배경 영상을 얻을 수 있다. 제안한 방법은 전역 움직임 및 전체 파노라마 합성 과정에서 수동 작업을 배제하여 파노라마 합성 과정을 일반화시켰다고 할 수 있다. 성능 평가를 위해 실제 방송에서 사용되는 축구 경기 영상에 제안한 알고리즘을 적용하고 기존의 알고리즘과 비교를 통해 그 우수성을 검증한다.

• ETRI Journal
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• 제34권1호
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• pp.9-16
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• 2012

Precoding in the multiple-input multiple-output orthogonal frequency division multiplexing system is investigated. In conventional wideband precoding (WBP), only one precoder, obtained from the decomposition of the subcarrier independent channel matrix, is used for all subcarriers. With an investigation of the relationship between the subcarrier independent channel matrix and the temporal/frequency channels, an improved WBP scheme is proposed for practical scenarios in which a part of subcarriers are allocated to a user. The improved WBP scheme is a generalized scheme of which narrow-band precoding and conventional WBP schemes are special modes. Simulation results demonstrate that the improved WBP scheme almost achieves the optimum performance of a single precoder and outperforms the conventional WBP scheme in terms of the bit error ratio and ergodic capacity with slight complexity increase. The largest advantage of the improved WBP scheme on signal-to-noise ratio in simulation results is over 2.1 dB.

• 한국음향학회지
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• 제21권3호
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• pp.256-263
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• 2002

본 연구에서는 백색 가우시안 잡음이 부가되는 환경 (AWGN)에서 측정 신호로부터 주파수와 진폭의 시간적 변동 특성을 추적하는 문제를 고려한다. 확장 칼만 필터는 여러 가지 응용분야에서 이용되고 있으며, 특히 시간적으로 변동하는 주파수를 추적하는 문제에도 응용되어 왔다. 기존의 확장 칼만 필터 주파수 추적기는 시간에 대한 신호 진폭의 변화폭이 적은 경우에 대해 유도되었거나 진폭의 시간적 변화폭이 큰 경우에는 부가적인 진폭 추적기가 요구된다. 본 연구에서는 시간에 따를 진폭의 변화폭이 상대적으로 큰 경우에 시변 주파수의 추적 성능을 높이기 위해 주파수와 진폭을 동시에 추적하는 확장 칼만 필터 주파수-진폭 추적기를 제안하고 수치모의 실험과 실제 실험을 통하여 그 성능을 확인한다.

• ETRI Journal
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• 제31권1호
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• pp.21-30
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• 2009

In low bit-rate video transmission, the payload of a single packet can often contain a whole coded frame due to the high compression ratio in both spatial and temporal domains of most modern video coders. Thus, the loss of a single packet not only causes the loss of a whole frame, but also produces error propagation into subsequent frames. In this paper, we propose a novel whole frame error concealment algorithm which reconstructs the first of the subsequent frames instead of the current lost frame to suppress the effects of error propagation. In the proposed algorithm, we impose a constraint which uses side match distortion (SMD) and overlapped region difference (ORD) to estimate motion vectors between the target reconstructed frame and its reference frame. SMD measures the spatial smoothness connection between a block and its neighboring blocks. ORD is defined as the difference between the correlated pixels which are predicted from one reference pixel. Experimental results show that the proposed algorithm effectively suppresses error propagation and significantly outperforms other conventional techniques in terms of both peak signal-to-noise ratio performance and subjective visual quality.

• Smart Structures and Systems
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• 제20권2호
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• pp.207-217
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• 2017

Because of the inevitable uncertainties such as structural parameters, external excitations and measurement noises, the effects of uncertainties should be taken into consideration in structural damage detection. In this paper, two probabilistic structural damage detection approaches are proposed to account for the underlying uncertainties in structural parameters and external excitation. The first approach adopts the statistical moment-based structural damage detection (SMBDD) algorithm together with the sensitivity analysis of the damage vector to the uncertain parameters. The approach takes the advantage of the strength SMBDD, so it is robust to measurement noise. However, it requests the number of measured responses is not less than that of unknown structural parameters. To reduce the number of measurements requested by the SMBDD algorithm, another probabilistic structural damage detection approach is proposed. It is based on the integration of structural damage detection using temporal moments in each time segment of measured response time history with the sensitivity analysis of the damage vector to the uncertain parameters. In both approaches, probability distribution of damage vector is estimated from those of uncertain parameters based on stochastic finite element model updating and probabilistic propagation. By comparing the two probability distribution characteristics for the undamaged and damaged models, probability of damage existence and damage extent at structural element level can be detected. Some numerical examples are used to demonstrate the performances of the two proposed approaches, respectively.

• 대한치과의사협회지
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• 제38권6호통권373호
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• pp.549-557
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• 2000

ㆍPurpose: This study was performed to investigate the initial conservative treatment for TMD patients using careful counselling and medication prospectively. ㆍMaterials and Methods: Careful counselling and medication were performed in 51 TMD patients and 27 patients had follow-up check 2 months or more. Diagnosis of TMD was based on medical history and, physical and radiographic examination. TMD included masticatory disorder, internal derangement, degenerative joint disease, inflammatory joint disorder. and problems resulting from extrinsic trauma. All patients had chief complaints of TMJ pain, mouth-opening limitation. joint noise, and/or referred pain. We counselled and explained to the patient about the pathogenesis, etiologic factors, diagnosis and treatment plan for abut 10 minutes. We prescribed nonsteroidal anti-inflammatorv analgesic(Somalgen) and amitriptyline 10mg per day for 2 weeks. We informed the patient of the attention sheet and taught self-exercise of jaw. The patient were assessed by answering the questionnaire of subjective evaluation of TMD & maxillofacial pain. Questionnaire of an activity limitation. Questionnaire of a jaw function, and Questionnaire for the evaluation of TMD. ㆍResults: In questionnaire for the evaluation of TMD, 88.5% of 26 patients answered that the treatment was efficacious. 71.4% of 21 patients answered no problem in everyday life. There were significant differences between pretreatment and final follow-up in the evaluation of the subjective pain in the following sections: opening widely, chewing, resting, morning, masticatory muscle, and temporal portion(SAS program, paired T-test, P = 0.05). ㆍConclusions: Considerate counselling and proper medication could be significantly effectve in the initial treatment of TMD.

• 한국항행학회논문지
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• 제21권3호
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• pp.243-250
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• 2017

GPS 신호체계는 대역확산 방식을 사용하며, 신호의 크기는 시스템 잡음수준 이하이므로 외부 전파 간섭신호에 매우 취약하며, 이는 GPS를 이용하는 선박 또는 항공기 에 대한 안전 운항을 제한 할 수 있다. 본 논문은 이러한 GPS 간섭 신호 제거를 위한 K-median 방식의 문턱치 설정 방식을 적용한 주파수 영역의 신호 처리 기법을 제안하며, 이는 기존에 보편적으로 사용되는 시간 영역에서의 간섭신호 제거 방식보다, 시간에 따른 신호 변화가 큰 간섭신호를 인가한 조건에 대해서 상대적으로 우수한 성능을 가짐을 확인하였다.