• 항공우주시스템공학회지
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• 제15권2호
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• pp.1-9
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• 2021

In this paper, a thickness compensation function is introduced to consider the shear deformation and warping effect resulting from increased thickness in the composite multi-cell wing box. The thickness compensation function is used to perform the structure optimization of the multi-cell. It is determined by minimizing the error of an analytical formula using solid mechanics and the Ritz method. It is used to define a structural performance prediction expression due to the increase in thickness. The parameter is defined by the number of spars and analyzed by the critical buckling load and the limited failure index as a response. Constraints in structural optimization are composed of displacements, torsional angles, the critical buckling load, and the failure index. The objective function is the mass, and its optimization is performed using a genetic algorithm.

• Structural Monitoring and Maintenance
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• 제9권4호
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• pp.373-388
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• 2022

A USW based diagnostic procedure is presented for estimating the depth of surface-breaking cracks. The diagnosis is demonstrated on seven lab-scale SFRC beam specimens, which are subjected to the CMOD controlled three-point bending test to create real bending cracks. Then, the recorded multiple ultrasonic signals are examined with the signal processing techniques, including wavelet transform and two-dimensional Fourier transform, to investigate the relationships between the crack depth and two diagnostic indices, namely the attenuation coefficient and dispersion index (DI). Finally, the reliabilities of these indices for depth estimation are verified with the visually measured crack depths as well as the crack features obtained with a digital image processing algorithm. It is found that the DI outperforms the attenuation coefficient in depth estimation, where this index displays good agreement with the visual inspection for 86% of the inspected specimens.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2021년도 봄 학술논문 발표대회
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• pp.27-28
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• 2021

For Barrier-Free certification, the floor and ground surfaces must be finished with materials that are not slippery, flat, and have low-impact in fallis. However, the BF Certification Act does not provide specific methods to meet these regulations. In performance-based design, the responsibility of proving the performance rests with the building owner and architect, so quantitative evaluation indexes are needed to select suitable materials. Furthermore, changes in performance after completion should be checked periodically in 'As-Is' conditions. There are various methods for slips, trips and falls risk assessment, causing confusion for users. In this study, the results of previous studies on the evaluation methods of slips, trips and falls were considered closely, and each quantitative evaluation index that can be used in the new construction and maintenance phase was presented.

• Journal of Information Processing Systems
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• 제9권4호
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• pp.511-537
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• 2013

Numerous data intensive applications demand the efficient processing of a new type of query, which is called a progressive query (PQ). A PQ consists of a set of unpredictable but inter-related step-queries (SQ) that are specified by its user in a sequence of steps. A conventional DBMS was not designed to efficiently process such PQs. In our earlier work, we introduced a materialized view based approach for efficiently processing PQs, where the focus was on selecting promising views for materialization. The problem of how to efficiently find usable views from the materialized set in order to answer the SQs for a PQ remains open. In this paper, we present a new index technique, called the Dynamic Materialized View Index (DMVI), to rapidly discover usable views for answering a given SQ. The structure of the proposed index is a special ordered tree where the SQ domain tables are used as search keys and some bitmaps are kept at the leaf nodes for refined filtering. A two-level priority rule is adopted to order domain tables in the tree, which facilitates the efficient maintenance of the tree by taking into account the dynamic characteristics of various types of materialized views for PQs. The bitmap encoding methods and the strategies/algorithms to construct, search, and maintain the DMVI are suggested. The extensive experimental results demonstrate that our index technique is quite promising in improving the performance of the materialized view based query processing approach for PQs.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제17권11호
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• pp.2945-2965
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• 2023

The laser inertial measurement unit is a precision device widely used in rocket navigation system and other equipment, and its quality is directly related to navigation accuracy. In the quality evaluation of laser inertial measurement unit, there is inevitably uncertainty in the index input information. First, the input numerical information is in interval form. Second, the index input grade and the quality evaluation result grade are given according to different national standards. So, it is a key step to transform the interval information input by the index into the data form consistent with the evaluation result grade. In the case of uncertain input, this paper puts forward a method based on probability distribution to solve the problem of asymmetry between the reference grade given by the index and the evaluation result grade when evaluating the quality of laser inertial measurement unit. By mapping the numerical relationship between the designated reference level and the evaluation reference level of the index information under different distributions, the index evidence symmetrical with the evaluation reference level is given. After the uncertain input information is transformed into evidence of interval degree distribution by this method, the information fusion of interval degree distribution evidence is carried out by interval evidential reasoning algorithm, and the evaluation result is obtained by projection covariance matrix adaptive evolution strategy optimization. Taking a five-meter redundant laser inertial measurement unit as an example, the applicability and effectiveness of this method are verified.

• 대한영양사협회학술지
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• 제20권2호
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• pp.123-132
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• 2014

This study investigated the effect of food consumption monitoring and real-time communication-based weight control program using a smartphone on weight reduction and maintenance in obese women. This study consisted of two phases: an 8-week weight control program with food consumption monitoring and real-time communication using a smartphone and an 8-week follow-up. Sixteen obese female college students (>30% body fat) participated in this program, and we measured changes in body composition and dietary intake volume. Follow-up analysis focused on weight maintenance after 8 weeks of no contact. Total energy intake (P<0.01), body weight (P<0.001), percent body fat (P<0.001), body fat (P<0.05), and body mass index (P <0.001) decreased significantly after the 8-week weight control program. However, we could not observe total energy intake or body composition regain after the follow-up period. These results suggest that food consumption monitoring and real-time communication using a smartphone can be effective for weight control and maintenance.

• 교육녹색환경연구
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• 제19권2호
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• pp.32-40
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• 2020

본 연구는 장애학생의 교육받을 권리와 공정한 지역배치 원리를 고려한 특수교육시설의 정비가 될 수 있도록 특수교육시설의 지역별 정비현황의 편차를 파악하고, 그 특성을 분석·고찰함으로써, 앞으로의 시설설립계획에 있어서 기초자료를 제공하고자 본 연구를 진행하게 되었다. 이를 위하여 교육부 특수교육원, 특수교육정책과, 각 시도교육청의 통계자료 및 시설자료를 활용하여 특수교육대상자와 장애영역별 현황을 중심으로 지역마다 주요현황 및 정비지수를 산출하였다. 분석결과, 일반적으로 대도시의 경우는 특수학교의 시설부족으로 인해, 특수학급과 일반학급에 의존하는 경향을 보였고, 지방도시에서는 장애영역별로 불균등한 결과를 보이며, 특수교육지원센터가 부족한 체계를 보완하는 것으로 보인다. 전체적으로 평가해보면, 특수교육시설은 아직 전국적으로 평준화되지 않는 정비 상황을 보인다.

• 한국ITS학회 논문지
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• 제22권2호
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• pp.15-28
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• 2023

경계역은 수도권 도시철도 연락운임정산에서 반영되지 못한 평가지표이다. 경계역은 동일한 노선을 공유하는 2개 운송기관의 경계 지점에 있는 역사로서 선로 운영방식은 영업관리와 유지관리로 구분된다. 지금까지 연락운임정산은 경계역을 영업관리의 관점으로 평가하였다. 한편 수도권 통합대중교통 요금체계는 발전적 차원에서 경계역을 유지관리의 관점으로 해석할 필요성을 요구하고 있다. 본 연구는 유지관리 방식이 도입되는 상황을 염두에 두고 수입금 변화를 정량적으로 분석하는 방안을 마련하였다. 서울교통공사와 KORAIL의 4개 구간의 경계역을 대상으로하여 1일 교통카드자료를 기반으로 운송기관의 수입금 변화를 평가하였다. 본 연구는 향후 수도권 도시철도의 운송수입금 변화를 평가하고 배분하는 분석적 판단을 위한 기초연구로써 의의가 있다고 할 수 있다.

• 한국농공학회논문집
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• 제58권4호
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• pp.97-106
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• 2016

Since public facilities have high property values and are directly exposed to the flood hazard, they account for the highest share of disaster damages compared to other assets such as housing, industry, vehicle and agriculture in case of floods. Therefore, this study was conducted to develop and suggest the potential flood damage index for public facilities to evaluate potential flood damage of specific local government directly or indirectly as a tool for decision-making related to flood prevention, maintenance, management, and budget allocation. The flood damage assessment system proposed in this study was evaluated in 231 local governments nationwide. Evaluation results showed that higher values were obtained in Seoul metropolitan government, Gyeonggi-do (province), coastal areas in Gyeongsangnam-do (province), and Jeju island.

• 펄프종이기술
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• 제42권3호
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• pp.28-36
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• 2010

Today We have three full series of the annals of Joseon Dynasty. Taebaeksan volume which is one of them shows comparatively good maintenance but Taebaeksan volume also decomposed in patches. The size of cover and inner paper were increased in late Joseon Dynasty, but the weight, thickness and basis weight bears no relation to each other. The oxidation index of paper in annals of pre-periods of King Sunjo shows very high value. After the annals of King Sunjo, the oxidation index of paper is very similar to today's Hanji. L.a.b values of inner paper in the Taebaeksan volume are similar generally. The average length of fiber using image analysis soft ware is 8.08~9.92 mm, that like immediate value of measurement. The air fraction of fiber's range is 1.20~2.12%. It lower than today's Hanji. After considering the factors of the length of fiber, air fraction and FE-SEM, we reached that no difference between raw material of inner paper in the Taebaeksan volume.