• 한국컴퓨터정보학회:학술대회논문집
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• 한국컴퓨터정보학회 2021년도 제64차 하계학술대회논문집 29권2호
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• pp.223-224
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• 2021

Recently, k-farthest neighbor (kFN) queries have not as much attention as k-nearest neighbor (kNN) queries. Therefore, this study considers moving k-farthest neighbor (MkFN) queries for spatial network databases. Given a positive integer k, a moving query point q, and a set of data points P, MkFN queries can constantly retrieve k data points that are farthest from the query point q. The challenge with processing MkFN queries in spatial networks is to avoid unnecessary or superfluous distance calculations between the query and associated data points. This study proposes a batch processing algorithm, called MOFA, to enable efficient processing of MkFN queries in spatial networks. MOFA aims to avoid dispensable distance computations based on the clustering of both query and data points. Moreover, a time complexity analysis is presented to clarify the effect of the clustering method on the query processing time. Extensive experiments using real-world roadmaps demonstrated the efficiency and scalability of the MOFA when compared with a conventional solution.

• International Journal of Advanced Culture Technology
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• 제11권2호
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• pp.10-29
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• 2023

Grit or perseverance as a factor for student success and life has gained increasing attention. Statistical methods have been the norm in analyzing various aspects of grit, but they do not address the transient and dynamic behavior well. We, for the first time, developed two linear dynamical models that specifically address the feedback structure of a child's desire to achieve a high grade point average (GPA) and the necessary effort that will increase stress between parents and a child. We call the dynamical model as GSES (Goal, Status, Effort & Stress). The two dynamical models incorporate the positive (i.e., achieving a high GPA) and the negative sides (i.e., effort and elevated stress and thus unhappiness) for being gritty or perseverant. Different types of parenting style and a child's characteristics were simulated whether parents and a child are empathetic or stubborn to their expectations and stress (i.e., willing or unwilling to change). Simulations show that when both parents and a child are empathetic to each other's expectation and stress, the most stable situations with minimal stress and effort occur. When a stubborn parent's and a stubborn child were studied together, this resulted in the highest elevation of stress and effort. Stubborn parents and a complying or empathetic child resulted in considerably high stress to a child. Interference from parents may unexpectedly result in a situation in which a child's stress is seriously elevated. The GSES model shows the U-shaped happiness curve (i.e., reciprocal of stress) caused by the increasing and then decreasing goal

• Structural Monitoring and Maintenance
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• 제10권4호
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• pp.299-314
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• 2023

Long-gauge carbon fiber line (CFL) sensors have received considerable attention in the past decade. However, there is still a need for an in-depth investigation of their measuring accuracy. This study investigates the accuracy of carbon fiber line sensors to monitor and differentiate the flexural behavior of two beams, one reinforced with steel bars alone and the other reinforced with steel and basalt fiber-reinforced polymer bars. A distributed set of long-gauge carbon fiber line, Fiber Bragg Grating (FBG), and traditional strain gauge sensors was mounted on the tensile concrete surface of the studied beams to compare the results and assess the accuracies of the proposed sensors. The test beams were loaded monotonically under four-point bending loading until failure. Results indicated the importance of using long-gauge sensors in providing useful, accurate, and reliable information regarding global structural behavior, while point sensors are affected by local damage and strain concentrations. Furthermore, long-gauge carbon fiber line sensors demonstrated good agreement with the corresponding Fiber Bragg Grating sensors with acceptable accuracy, thereby exhibiting potential for application in monitoring the health of large-scale structures.

• Structural Engineering and Mechanics
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• 제91권5호
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• pp.517-526
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• 2024

Due to the asymmetric cross-section of unequal-angle steel, the application of loads can induce axial rotation, leading to a series of buckling failure behaviors. Special attention must be paid during the design process. The present study aims to analyze the structural behavior of asymmetric steel angle members under various eccentric loading conditions, considering the complex biaxial bending interaction that arises when the angle steel is connected to the panel. Several key factors are investigated in this paper, including the effects of uniaxial and biaxial eccentricity on the structural behavior and the eccentric axial compression strength of long and short legs at different load application points. Potential risks associated with the specified load points, based on the AISC specifications, are also discussed. The study observed that the strength values of the members exhibited significant changes when the eccentric load deviates from the specified point. The relative position of the eccentric load point and the slenderness ratio of the member are critical influencing factors. Overall, this research intends to enhance the accuracy and reliability of strength analysis methods for asymmetric single angle steel members, providing valuable insights and guidance for a safer and more efficient design.

• 생태와환경
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• 제39권2호통권116호
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• pp.236-244
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• 2006

경안천 유입부(G 1)부터 팔당댐 앞 (P)까지의 2002년도 수질변동을 팔당호 전체 수질분포및 강우시기 등과 연동하여 평가하였다. 연평균 COD, 총인 및 총질소 농도는 경안천 유입부에서 댐 쪽으로 갈수록 농도가 크게 낮아지는 것으로 나타나, 경안천 유입하천의 높은 오염도가 직접 댐 앞 수질에 미치는 영향은 크지 않은 것으로 판단되었다. 조사시기 및 지점별 COD, 총인 및 총질소 농도는 강우기 (8, 9월)가 다른 조사시기에 비해 지점 간 차이가 적고, 초기농도도 상대적으로 낮았다. 클로로필 a 농도는 강우기 이후(10 ${\sim}$ 12월)보다는 이전(3${\sim}$6월)에 각 지점별 농도차이가 큰 것으로 나타났다. 팔당호 전체 수질분포에서, 북한강 유입수역 수온은 다른 수역에 비해 8월은 낮고 11월에는 높게 나타났다. COD와 SS농도는 강우기에는 각 수역별로 비교적 큰 농도차이를 보였으나 11월에는 큰 차이를 보이지 않았고, 농도도 낮았다. 4월 높았던 클로로필 a 농도는 강우기에는 현저하게 낮은 농도를 보였다. 4월에는 비교적 수심이 낮은 경안천 유입수역에서도 8월 및 11월에 비해 표층과 심층간의 수온 차가 크게 나타났다. 댐 앞 지점 SS농도는 4월에 표층에서 높고 8월에는 심층에서 높았다. 또한 COD, 총인, 총질소 농도는 8월이 4월에 비해 상 ${\cdot}$ 하층이 비교적 잘 혼합되고, 현저하게 낮은 농도를 보였으며, 11월에도 낮은 농도를 유지하고 있는 것으로 볼 때, 팔당호에서 수질관리에 집중해야 될 시기는 여름가을보다는 봄여름기간 중인 것으로 판단되었다.

• 한국물환경학회지
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• 제35권6호
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• pp.470-480
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• 2019

The Doam lake watershed was designated as a non-point pollution management area in 2007 to improve water quality based on watershed management implementation. There have been studies of non-point source reduction with respect to the watershed management impacting the pollutant transport of the reservoir. However, a little attention has been focused on the impact of water quality improvement by the management of the dam operation or the guidelines on the dam operation. In this study, the impact of in-lake management practices combined with watershed management is analyzed, and the appropriate guidelines on the operation of the dam are suggested. The integrated modeling system by coupling with the watershed model (HSPF) and reservoir water quality model (CE-QUAL-W2) was applied for analyzing the impact of water quality management practices. A scenario implemented with sedimentation basin and suspended matter barrier showed decrease in SS concentration up to 4.6%. The SS concentration increased in the scenarios adjusting withdrawal location from EL.673 m to the upper direction(EL.683 m and EL.688 m). The water quality was comparably high when the scenario implemented all in-lake practices with water intake at EL.673 m. However, there was improvement in water quality when the height of the water intake was moved to EL.688 m during the summer by preventing sediments inflow after the rainfall. Therefore, to manage water quality of the Doam lake, it is essential to control the water quality by modulating the height of water intake through consistent turbidity monitoring during rainfall.

• 한국강구조학회 논문집
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• 제28권3호
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• pp.173-183
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• 2016

본 연구에서는 HSA800 강재의 7종의 각종 시험을 실시하여 다양한 소재특성을 확인하였으며, 강도에 대한 균질성의 정량적 기준을 제안하였다. 또한 HSA800 강재가 강도에 대한 균질성의 기준을 만족하는지 검토하였다. 시험결과 HSA800 강재의 1/4지점의 소재 특성은 KS를 만족하며, 우수한 방향성, 저온에서의 내충격성이 나타났다. 또한, 제안한 강재의 강도에 대한 균질성의 기준을 만족하였다. 그러나, 마이크로조직시험 결과 2/4 지점에서 일부의 경우 조직이 뭉쳐있는 형태로 확인되어 주의가 요망된다.

• 한국병원경영학회지
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• 제19권2호
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• pp.34-43
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• 2014

This study was conducted to investigate the degree of nurses' knowledge, attitudes, and compliance with hospital infection standard precautions. The study subjects were nurses in a university hospital in Daegu, South Korea, and a self-administered survey was carried out using a standardized questionnaire from 1st to 15th August, 2012. A total of 187 questionnaires were used for analysis. Those who were injured by a syringe needle for the last year accounted for 29.96%, and those exposed to patients' blood or body fluid on their damaged skin/mucous membranes accounted for 26.2%. There were statistically significant differences in attitude and compliance according to safety environment for hospital infection standard precautions. The knowledge score of the subjects about standard precautions was $15.30{\pm}1.51$ on a 19 point scale and had significant difference according to the subjects' education level. The attitude score was $2.86{\pm}0.49$ on a 4 point scale and had significant difference depending on how experienced they were on the career. The compliance score was $3.41{\pm}0.38$ on a 4 point scale and had significant difference depending on their age and their experience on the career. In conclusion, it can be said that systematic and continuous practical training is required to improve compliance with standard precautions. Particularly, it is needed to provide less experienced nurses with educational opportunities along with their supervisors' ongoing attention and position personnel appropriately.

• 한국의류학회지
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• 제14권2호
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• pp.117-128
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• 1990

The purpose of this study is to find fitness of brassiere by means of body measuring value, its variation volume, the evaluation of perceptive image, and the evaluation of the sense of wearing. The results were as follows; 1) According to comparison for body measuring value before and after wearing brassiere, bust point (B.P.) height, lower bust height, upper chest circumference, chest circumference, and bust depth are increased, and lower chest circumference, bust point breadth, shoulder middle point - B.P., B.P. -under bust, and cup horizontal girth are decreased. 2) The difference of variation volume by material is not accepted. The part above $20\%$ at variation rate is under the region of the armpit, that is, the region connected arm from the back. 3) The subjects replied that they wore the brassiere in order to compensate the breast and needed to wear it regardless of thiness and obesity. They wore the brassiere in order to dress themselves in good shape, and felt that it put pressure upon the body, while it had nothing to do with adjusting bodily temperature and gave the sense of security. 4) The estimate of the sense of wearing by material is recognized as the difference of the attention at attentive level $1\%$. The multiple factor analysis of each item in the sense of wearing showed that the items which are explained over $90\%$ by common factors are '1. Unpreasant in touch', '2. The part of edge is haggard', '15. Not to be fit'.

• 한국정보과학회:학술대회논문집
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• 한국정보과학회 2011년도 한국컴퓨터종합학술대회논문집 Vol.38 No.1(C)
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• pp.112-114
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• 2011

On multimedia databases, in order to realize the fast access method, indexing methods for the multidimension data space are used. However, since it is a premise to use the Euclid distance as the distance measure, this method lacks in flexibility. On the other hand, there are metric indexing methods which require only to satisfy distance axiom. Since metric indexing methods can also apply for distance measures other than the Euclid distance, these methods have high flexibility. This paper proposes an improved method of VP-tree which is one of the metric indexing methods. VP-tree follows the node which suits the search range from a route node at searching. And distances between a query and all objects linked from the leaf node which finally arrived are computed, and it investigates whether each object is contained in the search range. However, search speed will become slow if the number of distance calculations in a leaf node increases. Therefore, we paid attention to the candidates selection method using the triangular inequality in a leaf node. As the improved methods, we propose a method to use the nearest neighbor object point for the query as the datum point of the triangular inequality. It becomes possible to make the search range smaller and to cut down the number of times of distance calculation by these improved methods. From evaluation experiments using 10,000 image data, it was found that our proposed method could cut 5%~12% of search time of the traditional method.