• 소음진동
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• 제9권5호
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• pp.991-997
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• 1999

It is getting higher the demand on a good sound in a car. Like some other sensory qualities, achieving a good sound is still treated as a black-box followed by the individual taste of tuning engineers. This study aims to define the attributes of a good car audio sound and the assessment factors affecting the sound quality. With a variety of surveys on professional listening groups and car audio installers, 26 most frequently used vocabularies are selected as typical presentations of car audio sound quality. After repetitions of listening tests with deliberately selected test CD, pre-recorded 15 different digital car-recordings, headphones replay system, and three different listening groups, it is proved that there are at least 5 different assessment factors which significantly affect the car audio sound quality. They are high fidelity, spectral balance, tonal accuracy, sound stage and acoustic fault.

• ETRI Journal
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• 제43권3호
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• pp.538-548
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• 2021

This paper proposes an approach to improve the performance of no-reference video quality assessment for sports videos with dynamic motion scenes using an efficient spatiotemporal model. In the proposed method, we divide the video sequences into video blocks and apply a 3D shearlet transform that can efficiently extract primary spatiotemporal features to capture dynamic natural motion scene statistics from the incoming video blocks. The concatenation of a deep residual bidirectional gated recurrent neural network and logistic regression is used to learn the spatiotemporal correlation more robustly and predict the perceptual quality score. In addition, conditional video block-wise constraints are incorporated into the objective function to improve quality estimation performance for the entire video. The experimental results show that the proposed method extracts spatiotemporal motion information more effectively and predicts the video quality with higher accuracy than the conventional no-reference video quality assessment methods.

• 한국멀티미디어학회논문지
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• 제23권12호
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• pp.1447-1453
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• 2020

In this paper, we propose a method for no-reference quality assessment of sports videos using 3D shearlet transform and deep residual neural networks. In the proposed method, 3D shearlet transform-based spatiotemporal features are extracted from the overlapped video blocks and applied to logistic regression concatenated with a deep residual neural network based on a conditional video block-wise constraint to learn the spatiotemporal correlation and predict the quality score. Our evaluation reveals that the proposed method predicts the video quality with higher accuracy than the conventional no-reference video quality assessment methods.

• 국제학술발표논문집
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• The 9th International Conference on Construction Engineering and Project Management
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• pp.1194-1201
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• 2022

The existing literature has witnessed the importance of productivity assessment and deducing factors affecting it. However, yet many models have shown limitations in practical applications in actual construction sites for process planning due to uncertainty and lack of data. This research presents a productivity assessment and database generation framework using simulation and compares the results with RSMeans to derive appropriate equipment combinations alternatives for earthwork operations. Data of 15 different conditions was collected from 5 different construction sites. Prediction accuracy above 90% were achieved for the simulation models with average error rate of 7.4%. The construction productivity assessment framework presented in this study is expected to be highly applicable to operation planning for earthwork operations.

• 국제학술발표논문집
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• The 6th International Conference on Construction Engineering and Project Management
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• pp.268-270
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• 2015

Overseas countries' government and facility management industries make efforts to ensure precise and fluent data from building information modeling (BIM). In facility management, a large amount of data and information are necessary to continue the process activities. Facility condition assessment, which is performed to make budget plan for the maintenance and operation requires the related facilities' documentation and information. However, it depends on the owner and the user of the facility to provide accurate and complete information to consultant. The problems as follows: (1) owner and user should provide documents and information, and (2) the consultant cannot verify the provided information. To solve these problems, we suggest a methodology to produce the information for FCA through BIM. First, all of the essential documentation and assessment elements are listed. Next, the documents and elements are separated out, whether they are able to be extracted from BIM or not. Then, the list indicates only the data that is linked with BIM. The suggestion is expected to provide the required information through the connection to BIM with accuracy and completeness and to present another BIM application use for facility management.

• 한국측량학회지
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• 제40권1호
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• pp.51-66
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• 2022

해수면온도는 지구 시스템에서 가장 중요한 메커니즘의 하나인 대기-해양의 상호작용을 단적으로 나타내며, 기후변화를 이해하는 데 필수적인 해양 기상요소이다. 이에, 공백 없이 시공간해상도가 일정한 격자자료는 해수면온도연구에 있어 그 활용도가 매우 높다. 이 논문에서는 2020년 해양 실측자료 137개 지점으로부터 최적화된 베리오그램을 도출하고 이를 이용한 정규크리깅을 통해 우리나라 주변해역의 일평균 해수면온도 격자지도를 산출하고 그 정확도를 평가하였다. 베리오그램 최적화는 가중최소제곱법을 이용하였고, 내삽정확도 검증을 위하여 공간적인 치우침이 없도록 객관적인 샘플링 기준을 적용하여 암맹평가를 수행하였다. 4회에 걸친 암맹평가 결과, 평균제곱근오차 0.995~1.035℃, 상관계수 0.981~0.982의 상당히 높은 정확도를 나타냈다. 계절별로는 여름철의 정확도가 상대적으로 약간 낮게 나타났는데, 이는 태풍의 영향으로 인한 급격한 수온 변동 때문으로 사료된다. 또한 가까운 바다보다 먼 바다에서, 동해, 남해보다 서해에서 상대적으로 정확도가 높게 나타났는데, 이는 가까운 바다에서 종종 반폐쇄해 지형으로 인해 해수의 물리적인 특성에 차이가 발생할 수 있기 때문인 것으로 보인다. 향후에는 계절별, 해역별 특성을 반영하는 SST 추정기법의 개선이 필요할 것이며, 개선된 자료는 우리나라 주변해역의 고품질 SST 합성장을 산출하는 앙상블 멤버로 활용될 수 있을 것으로 기대한다.

• 토지주택연구
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• 제3권1호
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• pp.69-78
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• 2012

본 연구에서는 토지적성평가 평가결과의 정확성을 향상시킬 수 있는 방안을 제시하였다. 이를 위해 지표값 측정 및 임계치 설정을 중심으로 현 제도에서 적용하고 있는 평가방법과 이를 개선할 수 있는 방안을 검토하고, 사례지역을 대상으로 두 가지 방법을 적용함으로써 기존의 방법에 비해 지니는 효과를 파악하였다. 구체적인 분석과정은 1) 공간적 입지특성에 대한 거리측정시 저항을 고려한 분석, 2) 보전적성값 산정시 물리적 특성지표에 적용되는 귀속도 함수의 임계치 설정에 따른 평가결과를 측정하였다. 평가결과 첫째, 저항을 고려한 측정방법이 단순한 직선거리에 의한 방법에 비해 하천이나 임야 등 접근성이 떨어지는 지역적 특성을 보다 잘 반영하고 있는 것으로 나타났다. 둘째, 대상지역의 최고값을 최대임계치로 설정하는 현재의 방법이 지표의 측정값 분포를 고려한 임계치 설정 때보다 상대적으로 평가절하된 점수값을 도출할 수 있음을 예측할 수 있었다. 마지막으로 인공위성영상자료를 평가결과에 중첩시켜 보았을 때 본 연구의 방법에 의한 적성등급이 현황과 보다 잘 부합하는 것으로 나타났다. 본 연구에서 제시한 평가방법은 토지적성평가 결과의 정확성을 향상시켜 준다는 점에서 의의가 크다. 더불어 그간 제도의 시행과정에서 나타난 문제점--평가단위의 문제, 평가절차상의 문제, 기초자료 정비의 문제 등--이 보완된다면 국토 및 도시정책 수립시 이를 효과적으로 지원할 수 있는 공간의사결정지원체계(SDSS)로서도 활용될 수 있을 것이다.

• 대한원격탐사학회지
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• 제34권4호
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• pp.601-610
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• 2018

The national accuracy of global land cover (GLC) products is of great importance to ecological and environmental research. However, GLC products that are derived from different satellite sensors, with differing spatial resolutions, classification methods, and classification schemes are certain to show some discrepancies. The goal of this study is to assess the accuracy of four commonly used GLC datasets in South Korea, GLC2000, GlobCover2009, MCD12Q1, and GlobeLand30. First, we compared the area of seven classes between four GLC datasets and a reference dataset. Then, we calculated the accuracy of the four GLC datasets based on an aggregated classification scheme containing seven classes, using overall, producer's and user's accuracies, and kappa coefficient. GlobeLand30 had the highest overall accuracy (77.59%). The overall accuracies of MCD12Q1, GLC2000, and GlobCover2009 were 75.51%, 68.38%, and 57.99%, respectively. These results indicate that GlobeLand30 is the most suitable dataset to support a variety of national scientific endeavors in South Korea.

• 한국응급구조학회지
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• 제19권1호
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• pp.7-17
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• 2015

Purpose: We gathered information for the development of a blood pressure measurement education program by analyzing the accuracy of reading taken using a blood pressure simulator by Korean paramedic students. Methods: Data from 131 students were collected in November 12-20, 2013, and April 2-4, 2014. A 27-item questionnaire was administered, the accuracy of measurements confirmed using a blood pressure simulator (BT-CEAB), and the data analyzed (SPSS v 21.0). Results: The accuracy of systolic and diastolic blood pressure readings (${\leq}2mmHg$) was relatively low (27.5%). The mean blood pressure knowledge score was 67.61 points; significant differences were noted considering the sex (p = .001), hours of practice (p =.007), numbers of practice (p = .001), and reported self-confidence (p = .026). The blood pressure measurement accuracy group did not show a significant difference in its knowledge of blood pressure (p = .198). Conclusion: Most subjects needed several practice sessions to master the skill of measuring blood pressure. The feedback provided by individual assessment and the practice education program will serve as the basis for clinical and prehospital practice.

• Nuclear Engineering and Technology
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• 제49권5호
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• pp.1100-1108
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• 2017

A thermal-hydraulic system code is an essential tool for the design and safety analysis of a nuclear power plant, and its accuracy quantification is very important for the code assessment and applications. The fast Fourier transform-based method (FFTBM) by signal mirroring (FFTBM-SM) has been used to quantify the accuracy of a system code by using a comparison of the experimental data and the calculated results. The method is an improved version of the FFTBM, and it is known that the FFTBM-SM judges the code accuracy in a more consistent and unbiased way. However, in some applications, unrealistic results have been obtained. In this study, it was found that accuracy quantification by FFTBM-SM is dependent on the frequency spectrum of the fast Fourier transform of experimental and error signals. The primary objective of this study is to reduce the frequency dependency of FFTBM-SM evaluation. For this, it was proposed to reduce the cut off frequency, which was introduced to cut off spurious contributions, in FFTBM-SM. A method to determine an appropriate cut off frequency was also proposed. The FFTBM-SM with the modified cut off frequency showed a significant improvement of the accuracy quantification.