• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2005년도 학술발표회 논문집
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• pp.409-413
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• 2005

Even though the relative importance of length scale of flow system allow us to simplify three dimensional flow problem to one or two dimensional representation, many systems still require three dimensional analysis. The objective of this study is to develop an efficient and accurate finite element model for analyzing and predicting three dimensional flow features in natural rivers and to offend to model spreading of pollutants and transport of sediments in the future. Firstly, three dimensional Reynolds averaged Navier-Stokes equations with the hydrostatic pressure assumption in generalized curvilinear coordinates were combined with the kinematic free-surface condition. Secondly. to simulate realistic high Reynolds number flow, the model employed the Streamline Upwind/Petrov-Galerkin(SU/PG) scheme as a weighting function for the finite element method in conjunction with an appropriate turbulence model(Smagorinsky scheme for the horizontal plain and Mellor-Yamada scheme for the vertical direction). Several tests is performed for the purpose of validation and verification of the developed model. A simple rectangular channel, 5-shaped and U-shaped channel are used for tests and comparisons are made with RMA-10 model. Runs for each case is converged stably without a oscillation and calculated water-surface deformation, longitudinal and transversal velocities, and velocity vector fields are in good agreement with the results of RMA-10 model.

• Advances in nano research
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• 제13권4호
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• pp.351-368
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• 2022

Recently, promising structural technologies like multi-function, ultra-load bearing capacity and tailored structures have been put up for discussions. Finite Element (FE) modelling is probably the best-known option capable of treating these superior properties and multi-domain behavior structures. However, advanced materials such as Functionally Graded Material (FGM) and nanocomposites suffer from problems resulting from variable material properties, reinforcement aggregation and mesh generation. Motivated by these factors, this research proposes a unified shape function for FGM, nanocomposites, graded nanocomposites, in addition to traditional isotropic and orthotropic structural materials. It depends not only on element length but also on the beam's material properties and geometric characteristics. The systematic mathematical theory and FE formulations are based on the Timoshenko beam theory for beam structure. Furthermore, the introduced element achieves C1 degree of continuity. The model is proved to be convergent and free-off shear locking. Moreover, numerical results for static and free vibration analysis support the model accuracy and capabilities by validation with different references. The proposed technique overcomes the issue of continuous properties modelling of these promising materials without discarding older ones. Therefore, introduced benchmark improvements on the FE old concept could be extended to help the development of new software features to confront the rapid progress of structural materials.

• 임상간호연구
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• 제18권1호
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• pp.159-170
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• 2012

Purpose: This study was designed to examine the validity of the evidence-based guideline on pain developed by Registered Nurses Association of Ontario(RNAO) translated into Korean based on the experts' opinions. Methods: The panel consisted of experts of 60 registered nurses in surgical units, medical doctors and nursing managers who were experts in pain assessment and management. The validity of translated RNAO guideline was evaluated in terms of appropriateness, applicability, and utilization in current practice. Appropriateness and applicability of each recommendation were measured with 9 point scale, whereas utilization was measured by yes/no question. Data were analyzed by mean, standard deviation, and percent. The experts' opinions were analyzed by content analysis method. Results: In general, most of the recommendations in the guideline received above 7 point in appropriateness and applicability. However, above 20% of recommendations showed less than 50% of utilization rates in current practice. Conclusion: The reasons for low utilization of recommendations in current practice are in need for investigation. This study can be used for the development of guideline more acceptable in Korean health care settings and improve the quality of care for the abdominal surgery patients suffering from pain in Korea.

• 여성건강간호학회지
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• 제27권2호
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• pp.153-165
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• 2021

Purpose: This study aimed to develop the following scales on women's environmental health and to examine their validity and reliability: severity, susceptibility, response efficacy, self-efficacy, benefit, barrier, personal health behavior, and community health behavior scales. Methods: The item pool was generated based on related scales, a wide literature review, and indepth interviews on women's environmental health according to the revised Rogers' protection motivation theory model. Content validity was verified by three nursing professionals. Exploratory factor analysis, convergent validity, and internal consistency reliability were examined. Results: The scales included 10 items on severity, 11 on susceptibility, 10 on response efficacy, 14 on self-efficacy, 8 on benefits, 10 on barriers, 17 on personal health behavior, and 16 on community health behavior. Convergent validity with the environmental behavior scale for female adolescents was supported. The Cronbach's α values for internal consistency were good for all scales: severity, . 84; susceptibility, .92; response efficacy, .88; self-efficacy, .90; benefits, .91; barriers, .85; personal health behavior, .90; and community health behavior, .91. Conclusion: The evaluation of the psychometric properties shows that these scales are valid and reliable measures of women's environmental health awareness and behaviors. These scales may be helpful for assessing women's environmental health behaviors, thereby contributing to efforts to promote environmental health.

• Smart Structures and Systems
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• 제3권4호
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• pp.475-494
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• 2007

This paper deals with the development of an innovative distributed construction system based on smart prefabricated concrete elements for the real-time condition assessment of civil infrastructure. So far, two reduced-scale prototypes have been produced, each consisting of a $0.2{\times}0.3{\times}5.6$ m RC beam specifically designed for permanent instrumentation with 8 long-gauge Fiber Optic Sensors (FOS) at the lower edge. The sensing system is Fiber Bragg Grating (FBG)-based and can measure finite displacements both static and dynamic with a sample frequency of 625 Hz per channel. The performance of the system underwent validation in the laboratory. The scope of the experiment was to correlate changes in the dynamic response of the beams with different damage scenarios, using a direct modal strain approach. Each specimen was dynamically characterized in the undamaged state and in various damage conditions, simulating different cracking levels and recurrent deterioration scenarios, including cover spalling and corrosion of the reinforcement. The location and the extent of damage are evaluated by calculating damage indices which take account of changes in frequency and in strain-mode-shapes. The outcomes of the experiment demonstrate how the damage distribution detected by the system is fully compatible with the damage extent appraised by inspection.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제9권9호
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• pp.3635-3654
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• 2015

With the rapid development of smart devices and mobile Internet, the video application plays an increasingly important role on mobile devices. Understanding user behavior patterns is critical for optimized operation of mobile live streaming systems. On the other hand, volume based billing models on cloud services make it easier for video service providers to scale their services as well as to reduce the waste from oversized service capacities. In this paper, the watching behaviors of a commercial mobile live streaming system are studied in a content-centric manner. Our analysis captures the intrinsic correlation existing between popularity and watching intensity of programs due to the synchronized watching behaviors with program schedule. The watching pattern is further used to estimate traffic volume generated by the program, which is useful on data volume capacity reservation and billing strategy selection in cloud services. The traffic range of programs is estimated based on a naive popularity prediction. In cross validation, the traffic ranges of around 94% of programs are successfully estimated. In high popularity programs (>20000 viewers), the overestimated traffic is less than 15% of real happened traffic when using upper bound to estimate program traffic.

• Composites Research
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• 제36권4호
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• pp.253-258
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• 2023

교통수단의 발전은 이동이 불편한 장애인들의 이동권 보장을 실현하였지만 차량사고시 발생할 수 있는 장애인 탑승객의 안전 향상은 일반 승객좌석에 비해 낮다고 할 수 있다. 특히 갑자기 발생할 수 있는 후방 추돌 사고의 경우 장애인 탑승객의 머리와 목 부상에 취약한 것이 현실이다. 이에 본 연구에서는 휠체어 운송 차량의 후방 추돌 시 차량내 장애인 탑승객의 머리와 목 상해지수 개선을 위해 headrest를 관상면으로 3등분한 multi-layer headrest foam이 제안되었다. 간이 모델을 통한 저속 후방 추돌 해석을 통해 foam의 다양한 압축 특성을 부여하기 위한 stress scale factor의 범위가 선정되었으며, 해당 범위를 parameter로 지정하여 GA최적화가 수행되었다. 최적화결과를 통해 layer의 압축 특성에 따른 HIC와 NIC간의 상간관계 분석이 이뤄졌으며, HIC는 Front layer, NIC는 Mid layer의 압축 특성에 가장 민감하게 반응하였고 Rear layer의 압축 특성은 가장 낮게 나타났다. Validation model에 일반headrest와 최적화된 multi-layer headrest를 각각 배치하여 저속 후방 추돌 sled test 해석을 수행하였으며, 일반headrest대비 multi-layer headrest에서의 HIC와 NIC가 낮게 도출되었다. multi-layer headrest에서의 압축 거동 역시 명확하게 나타나 multi-layer headrest가 일반headrest대비 머리와 목의 상해지수 개선에 효과적인 것이 검증되었다.

• 환경영향평가
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• 제20권5호
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• pp.663-673
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• 2011

In the face of accelerating biodiversity loss and its significance in our coexistence with nature, biodiversity is becoming more crucial in sustainable development perspective. To estimate biodiversity in the future which provides valuable information for decision making system especially in the national level, a quantitative approach must be studied forehand as a baseline of the present status. In this study, we developed a large-scale map of Plant Species Richness (PSR, typical indicator of biodiversity) for Young-dong and Pyung-chang provinces. Due to the accessibility of appropriate data and advance of modelling techniques, reduction of variables without deteriorating the predictive power is considered by applying Genetic algorithm. In addition, a number of Correctly Classified Instances (CCI) with 10-fold cross validation which indicates the predictive power, was carried out for evaluation. This study, as a fundamental baseline, will be beneficial in future land work as well as ecosystem restoration business or other relevant decision making agenda.

• 스마트미디어저널
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• 제13권2호
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• pp.16-22
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• 2024

Greenhouse provides opportunities to have big yield effectively and efficiently. However, many resources are required, such as fertigation, a kind of solution of nutrient. Resources supply is essential to cultivate crops. Inadequate supply will hinder plant growth whereas the surplus results in waste. In this paper, we are especially interested in the fertigation supply. Further, excess fertigation leads to drainage which is difficult to purify and threatens the environment. To address this challenge, we aim to predict the desired amount of fertigation. To achieve this objective, we first establish a prototype to record the climate conditions inside a rose greenhouse using Internet of Things sensors. Simultaneously, the desired fertigation amount is obtained with the help of weight scale and historical data of fertigation supply and drainage. Second, a method is proposed to predict the desired fertigation by taking the sensors' data as input, with a time-series model. Extensive experimental results suggest the potential of our objective and method. To be specific, our method achieves an average MAE 0.032 in the validation datasets.

• 임상간호연구
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• 제15권1호
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• pp.93-106
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• 2009

Purpose: The purpose of this study was to develop a valid and reliable instrument to explore and measure job satisfaction as perceived by perioperative nurses, specifically from the perspective of contemporary perioperative nursing in Korea. Method: Items (69) were developed from the responses to two open-ended questions by 168 perioperative nurses in one teaching hospital; (a) reasons that make work enjoyable, (b) reasons that make work unpleasant. Finally 55 items were selected, excluding items with lower correlation with the total scale. The instrument was completed by 885 perioperative nurses from 89 different hospitals nationwide who were attending the annual conference of the Korean Association Operating Room Nurses (KAORN), yielding a response rate of 95.6%. Results: Ten factors were extracted by factor analysis, which explained 60.0% of the total variance; Reliability and internal consistency were established (Cronbach's alpha=.95). A smaller sample of 39 perioperative nurses completed the instrument on two occasions, with a 2-week interval between. Mean scores were computed and two sets of scores were analyzed by Weighted Kappa (W-Kappa=0.680, p=.029). Conclusion: This instrument is a concise, highly practical and flexible tool, which can be used for the perioperative nurse in a wide range of hospital settings.