• 대한음성학회지:말소리
• /
• 제57호
• /
• pp.113-122
• /
• 2006

Recently, many studies have been done for speech recognition in noisy environments. Particularly, the Aurora DB has been built as the common database for comparing the various feature extraction schemes. However, in general, the recognition models as well as the features have to be modified for effective noisy speech recognition. As the structure of the HTK is very complex, it is not easy to modify, the recognition engine. In this paper, we implemented a baseline recognizer based on the segmental K-means algorithm whose performance is comparable to the HTK in spite of the simplicity in its implementation.

• 한국전산구조공학회:학술대회논문집
• /
• 한국전산구조공학회 2003년도 봄 학술발표회 논문집
• /
• pp.443-450
• /
• 2003

System identification techniques can be used to build a baseline modal model for a flawed structure that has no modal information on its as-built state. The accuracy of a system identification proposed by Stubbs and Kim is analyzed for plate-girder bridges and its impact on the accuracy of damage detection in those structures is also analyzed. A laboratory-scale model plate-girder is experimentally tested and the initial four bending modes are examined for certain damage scenarios. The performance of individual baseline modal models is assessed by detecting damage in the model structure.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2012년도 추계학술대회 논문집
• /
• pp.750-755
• /
• 2012

In this study we conduct the optimal spot-weld layout design of vehicle body structure considering dynamic stiffness and side impact. We conduct both linear static analysis and nonlinear analysis with a baseline model to verify the process. 13 design variables will be selected for the effect analysis. Then, topology optimization is conducted to each selected design variable. The design constraints are formulated to improve the dynamic stiffness and side impact performance. Objective function is to set the density of weld component. Optimal spot-weld layout design are compared with the baseline model to show the improvement.

• 환경정책연구
• /
• 제6권2호
• /
• pp.27-45
• /
• 2007

본 연구에서는 효과적인 에너지 관리를 위한 경제학적 일반방법론을 기초로 경제적 주요 변수가 고려된 목표조정 및 이행실적 평가 방법론을 제시하였다. 에너지소비 및 원단위는 생산량, 생산구조 등 요인에 의해 직접 영향을 받는다. 따라서 본 연구에서는 목표달성시점의 실질 생산량을 반영해 베이스라인 및 목표 재조정을 하고 이에 기초해 목표달성 도를 평가하였다. 사례분석 결과, 생산량 변동을 고려한 베이스라인 및 목표조정 유무에 따라 평가결과의 차이가 있음을 확인하였다. 본 연구는 성과의 지속적 개선을 축으로 한 적합성 평가제도와 교토메카니즘 활용 과정에서 최근 활발하게 수행되고 있는 온실가스 배출량 검인증 제도에서 핵심이 되는 검증기준 마련에 활용될 수 있을 것으로 기대된다.

• Smart Structures and Systems
• /
• 제24권4호
• /
• pp.475-490
• /
• 2019

The detection of structural damage without a priori information on the healthy state is challenging. In order to address the issue, the study presents a baseline-free approach to detect damage in beam structures based on an actual influence line. In particular, a multi-segment function-fitting calculation is developed to extract the actual deflection influence line (DIL) of a damaged beam from bridge responses due to a passing vehicle. An intact basis function based on the measurement position is introduced. The damage index is defined as the difference between the actual DIL and a constructed function related to the intact basis, and the damage location is indicated based on the local peak value of the damage index curve. The damage basis function is formulated by using the detected damage location. Based on the intact and damage basis functions, damage severity is quantified by fitting the actual DIL using the least-square calculation. Both numerical and experimental examples are provided to investigate the feasibility of the proposed method. The results indicate that the present baseline-free approach is effective in detecting the damage of beam structures.

• 수면정신생리
• /
• 제15권2호
• /
• pp.82-86
• /
• 2008

목 적：폐쇄성 수면무호흡증은 수면분절과 수면구조의 변화를 초래해 야간 수면의 질을 저하시킨다. 이 연구에서는 폐쇄성 수면무호흡증 환자에서 야간 수면다원검사와 지속적 상기도 양압술 처방압력 검사 중에 나타나는 수면분절지수의 변화와 이와 관련된 요인을 비교하였다. 방 법：야간 수면다원검사 결과 수면무호흡증으로 진단되고 지속적 상기도 양압술 처방압력 검사를 받은 환자 103명을 대상으로 하였다. 대상군의 임상적 특징을 조사하였으며 기초 측정일과 양압술 시행일의 수면분절지수를 포함한 수면 변인들을 비교하였다. 두 검사 사이의 변인 비교는 짝짓기 t-test로, 수면분절지수와 수면 변인의 관계는 Pearson 상관 분석으로 하였다(p<0.05, 양측 검정). 결 과：양압술 시행 시 기초 측정일에 비하여, 1단계수면 분율(%)은 유의하게 감소하였고 렘수면 잠복시간(REM latency)은 유의하게 단축되었다. 2단계수면 분율(%), 서파수면 분율(%) 그리고 렘수면 분율(%)은 증가하였다(p<0.05). 수면분절지수는 기초 측정일 $29.0{\pm}13.8$, 양압술 시행일 $15.2{\pm}8.8$로 감소하였다(t=9.7, p<0.01). 수면분절지수와 수면효율(%) 및 총수면시간은 음의 상관관계(r=-0.60, p<0.01；r=-0.45, p<0.01)가, 호흡장애지수와는 양의 상관관계(r=0.28, p<0.01)가 있었다. 결 론：폐쇄성 수면무호흡증에서 수면분절지수는 야간수면의 분절 정도 및 질환의 중증도를 잘 반영해주고 있어 진료에 보조적인 가치가 있을 것이다.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• 제11권3호
• /
• pp.1614-1632
• /
• 2017

Bag of visual words is a popular model in human action recognition, but usually suffers from loss of spatial and temporal configuration information of local features, and large quantization error in its feature coding procedure. In this paper, to overcome the two deficiencies, we combine sparse coding with spatio-temporal pyramid for human action recognition, and regard this method as the baseline. More importantly, which is also the focus of this paper, we find that there is a hierarchical structure in feature vector constructed by the baseline method. To exploit the hierarchical structure information for better recognition accuracy, we propose a tree regularized classifier to convey the hierarchical structure information. The main contributions of this paper can be summarized as: first, we introduce a tree regularized classifier to encode the hierarchical structure information in feature vector for human action recognition. Second, we present an optimization algorithm to learn the parameters of the proposed classifier. Third, the performance of the proposed classifier is evaluated on YouTube, Hollywood2, and UCF50 datasets, the experimental results show that the proposed tree regularized classifier obtains better performance than SVM and other popular classifiers, and achieves promising results on the three datasets.

• Smart Structures and Systems
• /
• 제26권3호
• /
• pp.291-309
• /
• 2020

To study oceanic and meteorological problems related to climate change, Korea has been operating several ocean research stations (ORSs). In 2011, the Gageocho ORS was attacked by Typhoon Muifa, and its structural members and several observation devices were severely damaged. After this event, the Gageocho ORS was rehabilitated with 5 m height to account for 100-yr extreme wave height, and the vibration measurement system was equipped to monitor the structural vibrational characteristics including natural frequencies and modal damping ratios. In this study, a mass reallocation method is presented for structural model updating of the Gageocho ORS based on the experimentally identified natural frequencies. A preliminary finite element (FE) model was constructed based on design drawings, and several of the candidate baseline FE models were manually built, taking into account the different structural conditions such as corroded thickness. Among these candidate baseline FE models, the most reasonable baseline FE model was selected by comparing the differences between the identified and calculated natural frequencies; the most suitable baseline FE model was updated based on the identified modal properties, and by using the pattern search method, which is one of direct search optimization methods. The mass reallocation method is newly proposed as a means to determine the equivalent mass quantities along the height and in a floor. It was found that the natural frequencies calculated based on the updated FE model was very close to the identified natural frequencies. In conclusion, it is expected that these results, which were obtained by updating a baseline FE model, can be useful for establishing the reference database for jacket-type offshore structures, and assessing the structural integrity of the Gageocho ORS.

• 대한조선학회 특별논문집
• /
• 대한조선학회 2006년도 특별논문집
• /
• pp.53-58
• /
• 2006

When the vibration troubles occur on the ship structure during the sea trial, the rectification work is very restricted because of in-situ limitation. Usually the finite element method is used to improve vibration characteristics of the structure, but it takes lots of time and effort in modeling the structure and adjusting the finite element model in order to consider appropriate boundary conditions of a complex ship structure. Therefore, experimental methods have been in general suggested to obtain proper countermeasures without time-consuming in modeling. In this paper, FRF(frequency response function) synthesis method is applied to estimate natural frequency of the modified ship structure, which is obtained from experimental and numerical methods.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2006년도 춘계학술대회논문집
• /
• pp.176-180
• /
• 2006

When the vibration troubles occur on the ship structure during the sea trial, the rectification work is very restricted because of in-situ limitation. Usually, the finite element method is used to improve vibration characteristics of the structure, but it takes lots of time and effort in modeling the structure and adjusting the finite element model in order to consider appropriate boundary conditions of a complex ship structure. Therefore, experimental methods have been in general suggested to obtain proper countermeasures without time-consuming in modeling. In this paper, FRE(frequency response function) synthesis method is applied to estimate natural frequency of the modified ship structure, which is obtained from experimental and numerical methods.