• Journal of Aerospace System Engineering
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• v.15 no.2
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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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• v.9 no.4
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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.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2021.05a
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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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• v.9 no.4
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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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• v.17 no.11
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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.

• Journal of the Korean Dietetic Association
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• v.20 no.2
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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.

• The Journal of Sustainable Design and Educational Environment Research
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• v.19 no.2
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• pp.32-40
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• 2020

In order to establish a special school considering the rights of disabled students to receive education and the principle of fair regional placement, this study identified the deviation of regional maintenance status of special education facilities and analyzed and examined their characteristics to provide desirable basic data for the establishment of facilities in the future. As a research method, the main status and maintenance index for each region were calculated based on the status of each special education subject and the disability area by using the statistics and facility data of the Ministry of Education, Special Education Policy Division, and the Ministry of Education of each province. According to the analysis results, large cities tended to rely on special classes and general classes due to the lack of facilities at special schools, and local cities showed uneven results for each disability area and supplemented the system lacking special education support centers. In overall evaluation, special education facilities have not yet been leveled across the country.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.22 no.2
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• pp.15-28
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• 2023

Boundary Station is an evaluation index that was not reflected in the Seoul Metropolitan Urban Railroad Connected Eare Allocation. Boundary station is a station located at the boundary point of two transportation agencies sharing the same route, and track operation methods are divided into business management and maintenance management. Until now, the Connected Fare Allocation has evaluated the boundary stations from the perspective of business management. Meanwhile, the integrated public transportation fee system requires the need to interpret the boundary stations from the point of view of maintenance management at the developmental level. This study was prepared a measure to quantitatively analyze changes in income with the introduction of maintenance methods in mind. The Change in the income of operation agency evaluated based on the daily transportation card data for the boundary stations of the four Seoul Transportation Corporation and KORAIL sections. This study is meaningful as a basic research for an analytical judgment that evaluates and allocates changes in transportation income of Seoul Metropolitan Urban Railroad in the future.

• Journal of The Korean Society of Agricultural Engineers
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• v.58 no.4
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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.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.42 no.3
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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.