• Title/Summary/Keyword: applicability domain

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Dynamic analysis of porous functionally graded layered deep beams with viscoelastic core

  • Assie, Amr;Akbas, Seref D.;Kabeel, Abdallah M.;Abdelrahman, Alaa A.;Eltaher, Mohamed A.
    • Steel and Composite Structures
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    • v.43 no.1
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    • pp.79-90
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    • 2022
  • In this study, the dynamic behavior of functionally graded layered deep beams with viscoelastic core is investigated including the porosity effect. The material properties of functionally graded layers are assumed to vary continuously through thickness direction according to the power-law function. To investigate porosity effect in functionally graded layers, three different distribution models are considered. The viscoelastically cored deep beam is exposed to harmonic sinusoidal load. The composite beam is modeled based on plane stress assumption. The dynamic equations of motion of the composite beam are derived based on the Hamilton principle. Within the framework of the finite element method (FEM), 2D twelve -node plane element is exploited to discretize the space domain. The discretized finite element model is solved using the Newmark average acceleration technique. The validity of the developed procedure is demonstrated by comparing the obtained results and good agreement is detected. Parametric studies are conducted to demonstrate the applicability of the developed methodology to study and analyze the dynamic response of viscoelastically cored porous functionally graded deep beams. Effects of viscoelastic parameter, porosity parameter, graduation index on the dynamic behavior of porous functionally graded deep beams with viscoelastic core are investigated and discussed. Material damping and porosity have a significant effect on the forced vibration response under harmonic excitation force. Increasing the material viscosity parameters results in decreasing the vibrational amplitudes and increasing the vibration time period due to increasing damping effect. Obtained results are supportive for the design and manufacturing of such type of composite beam structures.

A new semi-analytical approach for bending, buckling and free vibration analyses of power law functionally graded beams

  • Du, Mengjie;Liu, Jun;Ye, Wenbin;Yang, Fan;Lin, Gao
    • Structural Engineering and Mechanics
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    • v.81 no.2
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    • pp.179-194
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    • 2022
  • The bending, buckling and free vibration responses of functionally graded material (FGM) beams are investigated semi-analytically by the scaled boundary finite element method (SBFEM) in this paper. In the concepts of the SBFEM, the dimension of computational domain can be reduced by one, therefore only the axial dimension of the beam is discretized using the higher order spectral element, which reduces the amount of calculation and greatly improves the calculation efficiency. The governing equation of FGM beams is derived in detail by the means of the principle of virtual work. Compared with the higher-order beam theory, fewer parameters and simpler control equations are used. And the governing equation is transformed into a first-order ordinary differential equation by introducing intermediate variables. Analytical solutions of the governing equation can be obtained by pade series expansion in the direction of thickness. Numerical example are compared with the numerical solutions provided by the previous researchers to verify the accuracy and applicability of the proposed method. The results show that the proposed formulations can quickly converge to the reference solutions by increasing the order of higher order spectral elements, and high accuracy can be achieved by using a small number of the elements. In addition, the influence of the structural sizes, material properties and boundary conditions on the mechanical behaviors of FG beams subjected to different load types is discussed.

Updates of Nursing Evidence-Based Practice Guideline for Indwelling Urinary Catheterization (근거기반 유치도뇨간호 실무지침 개정)

  • Park, Kyung Hee;Choo, Hee Jung;Seo, Hyun Ju;Hong, Hae Kyung;Lee, Joohyun;Lim, Kyung Choon
    • Journal of Korean Clinical Nursing Research
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    • v.29 no.3
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    • pp.211-222
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    • 2023
  • Purpose: This study was conducted to update the existing evidence-based nursing clinical practice guideline for indwelling urinary catheterization (IUC). Methods: The guideline have been revised in 22 steps based on international standards. The quality of the practice guidelines to be used for revision was evaluated using the Appraisal of Guidelines for Research and Evaluation II. The evaluation of the content appropriateness and applicability of the draft recommendations of the revised practice guidelines was performed using the RAND/UCLA Appropriateness Method, a decision-making method developed by the RAND Corporation. Four guidelines were used for the revision. Results: The updated nursing practice guideline for IUC consisted of 9 domains and 134 recommendations. The numbers of recommendations in each domain were: 4 Assessment, 20 Equipment, 11 Catheter insertion, 52 Catheter maintenance, 4 Catheter and drainage bag change, 9 Catheter removal, 22 Complications management, 5 Education and consult, and 7 Hospital support. The recommended grade was 8.2% for A, 38.1% for B, and 53.7% for C. Among these, the major revision was done in 11 recommendations (8.2%). A total of 29 recommendations (21.6%) were newly added. 30 (22.4%) recommendations had minor revisions such as changes or addition for some words or sentences, and 13 (9.7%) recommendations were deleted. Conclusion: Revised nursing practice guideline is expected to serve as an evidence-based practice guideline for IUC in Korea. This guideline will provide health care providers, patients, and caregivers with information to help manage IUC, leading to improved patient outcomes.

Instructional Design for Systems Thinking Education in Health Systems Science (의료시스템과학에서의 시스템사고 교육을 위한 교수설계)

  • Sejin Kim;Sangmi T Lee;Danbi Lee;Bo Young Yoon
    • Korean Medical Education Review
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    • v.25 no.3
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    • pp.212-228
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    • 2023
  • Systems thinking, a linking domain of health systems science (HSS), is an approach that investigates specific problems from a holistic perspective. It supports improving patients' health, fulfilling their health needs, and anticipating issues that threaten patient safety within the healthcare system. It also helps solve problems through critical thinking and ref lection. This study aimed to develop an curriculum on systems thinking, explore the effectiveness of the course, and investigate the applicability of HSS education at individual universities. In this study, the ADDIE (Analysis, Design, Development, Implementation, and Evaluation) model was utilized to design, develop, implement, and evaluate an elective course on systems thinking. In the design process, learning outcomes and goals were developed, and educational content, teaching-learning methods, and student evaluation methods were linked. In the development process, class materials and evaluation materials were prepared. In the implementation process, the course was implemented, and the evaluation process analyzed the results of learning performance and curriculum assessments. The evaluation found the following results. First, the students in the study realized the importance of systems thinking and experienced the need for systems thinking through non-medical and medical situations. Second, the students were very satisfied with the learning activities in the course (mean=4.84), and the results of the self-competence evaluation, conducted before and after the course, also showed a significant improvement. This study confirmed the effectiveness of the elective course, and its results can serve as a reference for developing an HSS curriculum.

Research on Driving Pattern Analysis Techniques Using Contrastive Learning Methods (대조학습 방법을 이용한 주행패턴 분석 기법 연구)

  • Hoe Jun Jeong;Seung Ha Kim;Joon Hee Kim;Jang Woo Kwon
    • The Journal of The Korea Institute of Intelligent Transport Systems
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    • v.23 no.1
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    • pp.182-196
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    • 2024
  • This study introduces driving pattern analysis and change detection methods using smartphone sensors, based on contrastive learning. These methods characterize driving patterns without labeled data, allowing accurate classification with minimal labeling. In addition, they are robust to domain changes, such as different vehicle types. The study also examined the applicability of these methods to smartphones by comparing them with six lightweight deep-learning models. This comparison supported the development of smartphone-based driving pattern analysis and assistance systems, utilizing smartphone sensors and contrastive learning to enhance driving safety and efficiency while reducing the need for extensive labeled data. This research offers a promising avenue for addressing contemporary transportation challenges and advancing intelligent transportation systems.

Deep Learning-based Professional Image Interpretation Using Expertise Transplant (전문성 이식을 통한 딥러닝 기반 전문 이미지 해석 방법론)

  • Kim, Taejin;Kim, Namgyu
    • Journal of Intelligence and Information Systems
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    • v.26 no.2
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    • pp.79-104
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    • 2020
  • Recently, as deep learning has attracted attention, the use of deep learning is being considered as a method for solving problems in various fields. In particular, deep learning is known to have excellent performance when applied to applying unstructured data such as text, sound and images, and many studies have proven its effectiveness. Owing to the remarkable development of text and image deep learning technology, interests in image captioning technology and its application is rapidly increasing. Image captioning is a technique that automatically generates relevant captions for a given image by handling both image comprehension and text generation simultaneously. In spite of the high entry barrier of image captioning that analysts should be able to process both image and text data, image captioning has established itself as one of the key fields in the A.I. research owing to its various applicability. In addition, many researches have been conducted to improve the performance of image captioning in various aspects. Recent researches attempt to create advanced captions that can not only describe an image accurately, but also convey the information contained in the image more sophisticatedly. Despite many recent efforts to improve the performance of image captioning, it is difficult to find any researches to interpret images from the perspective of domain experts in each field not from the perspective of the general public. Even for the same image, the part of interests may differ according to the professional field of the person who has encountered the image. Moreover, the way of interpreting and expressing the image also differs according to the level of expertise. The public tends to recognize the image from a holistic and general perspective, that is, from the perspective of identifying the image's constituent objects and their relationships. On the contrary, the domain experts tend to recognize the image by focusing on some specific elements necessary to interpret the given image based on their expertise. It implies that meaningful parts of an image are mutually different depending on viewers' perspective even for the same image. So, image captioning needs to implement this phenomenon. Therefore, in this study, we propose a method to generate captions specialized in each domain for the image by utilizing the expertise of experts in the corresponding domain. Specifically, after performing pre-training on a large amount of general data, the expertise in the field is transplanted through transfer-learning with a small amount of expertise data. However, simple adaption of transfer learning using expertise data may invoke another type of problems. Simultaneous learning with captions of various characteristics may invoke so-called 'inter-observation interference' problem, which make it difficult to perform pure learning of each characteristic point of view. For learning with vast amount of data, most of this interference is self-purified and has little impact on learning results. On the contrary, in the case of fine-tuning where learning is performed on a small amount of data, the impact of such interference on learning can be relatively large. To solve this problem, therefore, we propose a novel 'Character-Independent Transfer-learning' that performs transfer learning independently for each character. In order to confirm the feasibility of the proposed methodology, we performed experiments utilizing the results of pre-training on MSCOCO dataset which is comprised of 120,000 images and about 600,000 general captions. Additionally, according to the advice of an art therapist, about 300 pairs of 'image / expertise captions' were created, and the data was used for the experiments of expertise transplantation. As a result of the experiment, it was confirmed that the caption generated according to the proposed methodology generates captions from the perspective of implanted expertise whereas the caption generated through learning on general data contains a number of contents irrelevant to expertise interpretation. In this paper, we propose a novel approach of specialized image interpretation. To achieve this goal, we present a method to use transfer learning and generate captions specialized in the specific domain. In the future, by applying the proposed methodology to expertise transplant in various fields, we expected that many researches will be actively conducted to solve the problem of lack of expertise data and to improve performance of image captioning.

Predicting Migration of a Heavy Metal in a Sandy Soil Using Time Domain Reflectometry (TDR을 이용한 사질토양에서의 중금속 이동 추정)

  • Dong-Ju Kim;Doo-Sung Baek;Min-Soo Park
    • Journal of Korea Soil Environment Society
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    • v.4 no.1
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    • pp.109-118
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    • 1999
  • Recently, transport parameters of conservative solutes such as KCl in a porous medium have been successfully determined using time domain reflectometry (TDR) . This study was initiated to Investigate the applicability of TDR technique to monitoring the fate of a heavy metal ion in a sandy soil and the distribution of its concentration along travel distance with time. A column test was conducted in a laboratory that consists of monitoring both resident and flux concentrations of $ZnCl_2$in a sandy soil under a breakthrough condition. A tracer of $ZnCl_2$(10 g/L) was injected onto the top surface of the sample as pulse type as soon as a steady-state condition was achieved. Time-series measurements of resistance and electrical conductivity were performed at 10 cm and 20 cm of distances from the inlet boundary by horizontal-positioning of parallel TDR metallic rods and using an EC-meter for the effluent exiting the bottom boundary respectively. In addition. Zn ions of the effluent were analyzed by ICP-AES. Since the mode and position of concentration detected by TDR and effluent were different, comparison between ICP analysis and TDR-detected concentration was made by predicting flux concentration using CDE model accommodating a decay constant with the transport parameters obtained from the resident concentrations. The experimental results showed that the resident concentration resulted in earlier and higher peak than the flux concentration obtained by EC-meter, implying the homogeneity of the packed sandy soil. A close agreement was found between the predicted from the transport parameters obtained by TDR and the measured $ZnCl_2$concentration. This indicates that TDR technique can also be applied to monitoring heavy metal concentrations in the soil once that a decay constant is obtained for a given soil.

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Level Set based Topological Shape Optimization of Phononic Crystals (음향결정 구조의 레벨셋 기반 위상 및 형상 최적설계)

  • Kim, Min-Geun;Hashimoto, Hiroshi;Abe, Kazuhisa;Cho, Seonho
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.25 no.6
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    • pp.549-558
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    • 2012
  • A topology optimization method for phononic crystals is developed for the design of sound barriers, using the level set approach. Given a frequency and an incident wave to the phononic crystals, an optimal shape of periodic inclusions is found by minimizing the norm of transmittance. In a sound field including scattering bodies, an acoustic wave can be refracted on the obstacle boundaries, which enables to control acoustic performance by taking the shape of inclusions as the design variables. In this research, we consider a layered structure which is composed of inclusions arranged periodically in horizontal direction while finite inclusions are distributed in vertical direction. Due to the periodicity of inclusions, a unit cell can be considered to analyze the wave propagation together with proper boundary conditions which are imposed on the left and right edges of the unit cell using the Bloch theorem. The boundary conditions for the lower and the upper boundaries of unit cell are described by impedance matrices, which represent the transmission of waves between the layered structure and the semi-infinite external media. A level set method is employed to describe the topology and the shape of inclusions. In the level set method, the initial domain is kept fixed and its boundary is represented by an implicit moving boundary embedded in the level set function, which facilitates to handle complicated topological shape changes. Through several numerical examples, the applicability of the proposed method is demonstrated.

Building Wind Corridor Network Using Roughness Length (거칠기길이를 이용한 바람통로 네트워크 구축)

  • An, Seung Man;Lee, Kyoo-Seock;Yi, Chaeyeon
    • Journal of the Korean Institute of Landscape Architecture
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    • v.43 no.3
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    • pp.101-113
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    • 2015
  • The purpose of this study is increasing ventilation network usability for urban green space planning by enhancing its practicality and detail. A ventilation network feature extraction technique using roughness length($z_0$) was proposed. Continuously surfaced DZoMs generated from $z_0$(cadastral unit) using three interpolations(IDW, Spline, and Kriging) were compared to choose the most suitable interpolation method. Ventilation network features were extracted using the most suitable interpolation technique and studied with land cover and land surface temperature by spatial overlay comparison. Results show Kriging is most suitable for DZoM and feature extraction in comparison with IDW and Spline. Kriging based features are well fit to the land surface temperature(Landsat-7 ETM+) on summer and winter nights. Noteworthy is that the produced ventilation network appears to mitigate urban heat loads at night. The practical use of proposed ventilation network features are highly expected for urban green space planning, though strict validation and enhancement should follow. (1) $z_0$ enhancement, (2) additional ventilation network interpretation and editing, (3) linking disconnected ventilation network features, and (4) associated dataset enhancement with data integrity should technically preceded to enhance the applicability of a ventilation network for green space planning. The study domain will be expanded to the Seoul metropolitan area to apply the proposed ventilation network to green space planning practice.

Human Tutoring vs. Teachable Agent Tutoring: The Effectiveness of "Learning by Teaching" in TA Program on Cognition and Motivation

  • Lim, Ka-Ram;So, Yeon-Hee;Han, Cheon-Woo;Hwang, Su-Young;Ryu, Ki-Gon;Shin, Mo-Ran;Kim, Sung-Il
    • 한국HCI학회:학술대회논문집
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    • 2006.02a
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    • pp.945-953
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    • 2006
  • The researchers in the field of cognitive science and learning science suggest that the teaching activity induces the elaborative and meaningful learning. Actually, lots of research findings have shown the beneficial effect of learning by teaching such as peer tutoring. But peer tutoring has some limitations in the practical learning context. To overcome some limitations, the new concept of "learning by teaching" through the agent called Teachable Agent. The teachable agent is a modified version of traditional intelligent tutoring system that assigns a role of tutor to teach the agent. The teachable agent monitors individual difference and provides a student with a chance for deep learning and motivation to learn by allowing them to play an active role in the process of learning. That is, The teaching activity induces the elaborative and meaningful learning. This study compared the effects of our teachable agent, KORI, and peer tutoring on the cognition and motivation. The field experiment was conducted to examine whether learning by teaching the teachable agent would be more effective than peer tutoring and reading condition. In the experiment, all participants took 30 minutes lesson on rock and rock cycle together to acquire the base knowledge in the domain. After the lesson, participants were randomly assigned to one of the three experimental conditions; reading condition, peer tutoring condition, and teachable agent condition. Next, participants of each condition moved into separated place and performed their own learning activity. After finishing all of the learning activities in each condition, all participants were instructed to rate the interestingness using a 5-point scale on their own learning activity and leaning material, and were given the comprehension test. The results indicated that the teachable agent condition and the peer tutoring condition showed more interests in the learning than the reading condition. It is suggested that teachable agent has more advantages in overcoming the several practical limitations of peer tutoring such as restrictions in time and place, tutor's cognitive burden, unnecessary interaction during peer tutoring. The applicability and prospects of the teachable agent as an efficient substitute for peer tutoring and traditional intelligent tutoring system were also discussed.

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