• 제목/요약/키워드: calculation models

검색결과 1,098건 처리시간 0.031초

국내 물리치료분야에 대한 질적 평가와 근거 수준 및 권고 등급 모형 개발 방안 (Qualitative Assessment and Development of Level of Evidence and Strength of Recommendation Models in the Field of Physical Therapy in Korea)

  • 조성현;이정우
    • 대한통합의학회지
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    • 제11권2호
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    • pp.231-242
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    • 2023
  • Purpose : This study aimed to identify ways to improve the quality of physical therapy research and ultimately review the current situation to improve evidence-based decision-making in physical therapy. Methods : For better evidence-based decision-making in physical therapy, researchers should review the quality assessment of articles in more detail and report their findings for valid and appropriate level of evidence and strength of recommendations. The level of evidence affects how well the findings are derived from well-designed literature. The evaluation of the evidence focuses primarily on the study design and the degree of bias that may compromise the validity of the findings. The final recommendation is based on a combination of the study design and literature quality. To uncover gems of information in each paper, a risk of bias assessment should be performed after the literature has been initially selected. Results : Researchers should consider the complexity of the intervention, appropriate grouping, and calculation of effect sizes for the intervention. Researchers conducting systematic reviews should provide a detailed description of the quality assessment performed and present a detailed analysis of their interpretation of the results. The results of systematic reviews and meta-analyses should be interpreted with caution and include a risk of bias assessment. Guidelines for the level of evidence and strength of recommendations should be developed and utilized more broadly to improve reporting practices in physical therapy. Conclusion : Researchers should be knowledgeable about the strengths and limitations of each study design and methodology. In the future, researchers will also need to improve their ability to critically evaluate their findings, given the potential for their results to influence clinical practice.

A modified JFNK with line search method for solving k-eigenvalue neutronics problems with thermal-hydraulics feedback

  • Lixun Liu;Han Zhang;Yingjie Wu;Baokun Liu;Jiong Guo;Fu Li
    • Nuclear Engineering and Technology
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    • 제55권1호
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    • pp.310-323
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    • 2023
  • The k-eigenvalue neutronics/thermal-hydraulics coupling calculation is a key issue for reactor design and analysis. Jacobian-free Newton-Krylov (JFNK) method, featured with super-linear convergence rate and high efficiency, has been attracting more and more attention to solve the multi-physics coupling problem. However, it may converge to the high-order eigenmode because of the multiple solutions nature of the k-eigenvalue form of multi-physics coupling issue. Based on our previous work, a modified JFNK with a line search method is proposed in this work, which can find the fundamental eigenmode together with thermal-hydraulics feedback in a wide range of initial values. In detail, the existing modified JFNK method is combined with the line search strategy, so that the intermediate iterative solution can avoid a sudden divergence and be adjusted into a convergence basin smoothly. Two simplified 2-D homogeneous reactor models, a PWR model, and an HTR model, are utilized to evaluate the performance of the newly proposed JFNK method. The results show that the performance of this proposed JFNK is more robust than the existing JFNK-based methods.

Compressive behavior of concrete-filled square stainless steel tube stub columns

  • Dai, Peng;Yang, Lu;Wang, Jie;Ning, Keyang;Gang, Yi
    • Steel and Composite Structures
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    • 제42권1호
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    • pp.91-106
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    • 2022
  • Concrete-filled square stainless steel tubes (CFSSST), which possess relatively large flexural stiffness, high corrosion resistance and require simple joint configurations and low maintenance cost, have a great potential in constructional applications. Despite that the use of stainless steel may result in high initial cost compared to their conventional carbon steel counterparts, the whole-life cost of CFSSST is however considered to be lower, which offers a competitive choice in engineering practice. In this paper, a comprehensive experimental and numerical program on 24 CFSSST stub column specimens, including 3 austenitic and 3 duplex stainless steel square hollow section (SHS) stub columns and 9 austenitic and 9 duplex CFSSST stub columns, has been carried out. Finite element (FE) models were developed to be used in parametric analysis to investigate the influence of the tube thickness and concrete strength on the ultimate capacities more accurately. Comparisons of the experimental and numerical results with the predictions made by design guides ACI 318, ANSI/AISC 360, Eurocode 4 and GB 50936 have been performed. It was found that these design methods generally give conservative predictions to the ultimate capacities of CFSSST stub columns. Improved calculation methods, developed based on the Continuous Strength Method, have been proposed to provide more accurate estimations of the ultimate resistances of CFSSST stub columns. The suitability of these proposals has been validated by comparison with the test results, where a good agreement between the predictions and the test results have been achieved.

Empirical seismic vulnerability probability prediction model of RC structures considering historical field observation

  • Si-Qi Li;Hong-Bo Liu;Ke Du;Jia-Cheng Han;Yi-Ru Li;Li-Hui Yin
    • Structural Engineering and Mechanics
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    • 제86권4호
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    • pp.547-571
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    • 2023
  • To deeply probe the actual earthquake level and fragility of typical reinforced concrete (RC) structures under multiple intensity grades, considering diachronic measurement building stock samples and actual observations of representative catastrophic earth shocks in China from 1990 to 2010, RC structures were divided into traditional RC structures (TRCs) and bottom reinforced concrete frame seismic wall masonry (BFM) structures, and the empirical damage characteristics and mechanisms were analysed. A great deal of statistics and induction were developed on the historical experience investigation data of 59 typical catastrophic earthquakes in 9 provinces of China. The database and fragility matrix prediction model were established with TRCs of 4,122.5284×104 m2 and 5,844 buildings and BFMs of 5,872 buildings as empirical seismic damage samples. By employing the methods of structural damage probability and statistics, nonlinear prediction of seismic vulnerability, and numerical and applied functional analysis, the comparison matrix of actual fragility probability prediction of TRC and BFM in multiple intensity regions under the latest version of China's macrointensity standard was established. A novel nonlinear regression prediction model of seismic vulnerability was proposed, and prediction models considering the seismic damage ratio and transcendental probability parameters were constructed. The time-varying vulnerability comparative model of the sample database was developed according to the different periods of multiple earthquakes. The new calculation method of the average fragility prediction index (AFPI) matrix parameter model has been proposed to predict the seismic fragility of an areal RC structure.

가중치 VAE 오버샘플링(W-VAE)을 이용한 보안데이터셋 샘플링 기법 연구 (A Data Sampling Technique for Secure Dataset Using Weight VAE Oversampling(W-VAE))

  • 강한바다;이재우
    • 한국정보통신학회논문지
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    • 제26권12호
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    • pp.1872-1879
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    • 2022
  • 최근 인공지능 기술이 발전하면서 해킹 공격을 탐지하기 위해 인공지능을 이용하려는 연구가 활발히 진행되고 있다. 하지만, 인공지능 모델 개발에 핵심인 학습데이터를 구성하는데 있어서 보안데이터가 대표적인 불균형 데이터라는 점이 큰 장애물로 인식되고 있다. 이에 본 눈문에서는 오버샘플링을 위한 데이터 추출에 딥러닝 생성 모델인 VAE를 적용하고 K-NN을 이용한 가중치 계산을 통해 클래스별 오버샘플링 개수를 설정하여 샘플링을 하는 W-VAE 오버샘플링 기법을 제안한다. 본 논문에서는 공개 네트워크 보안 데이터셋인 NSL-KDD를 통해 ROS, SMOTE, ADASYN 등 총 5가지 오버샘플링 기법을 적용하였으며 본 논문에서 제안한 오버샘플링 기법이 F1-Score 평가지표를 통해 기존 오버샘플링 기법과 비교하여 가장 효과적인 샘플링 기법임을 증명하였다.

Study on seismic performance of shaking table model of full light-weight concrete utility tunnel

  • Yanmin Yang;Qi Yuan;Yongqing Li;Jingyu Li;Yuan Gao;Yuzhe Zou
    • Computers and Concrete
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    • 제32권1호
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    • pp.15-26
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    • 2023
  • In order to study the anti-seismic performance of full light-weight concrete utility tunnel, EL Centro seismic waves were input, and the seismic simulation shaking table test was carried out on the four utility tunnel models. The dynamic characteristics and acceleration response of the system consisting of the utility tunnel structure and the soil, and the interlayer displacement response of the structure were analyzed. The influence law of different construction methods, haunch heights and concrete types on the dynamic response of the utility tunnel structure was studied. And the experimental results were compared with the finite element calculation results. The results indicated that with the increase of seismic wave intensity, the natural frequency of the utility tunnel structure system decreased and the damping ratio increased. The assembling composite construction method could be equivalent to replace the integral cast-in-place construction method. The haunch height of the assembling composite full light-weight concrete utility tunnel was increased from 30 mm to 50 mm to enhance the anti-seismic performance during large earthquakes. The anti-seismic performance of the full light-weight concrete utility tunnel was better than that of the ordinary concrete utility tunnel. The peak acceleration of the structure was reduced by 21.8% and the interlayer displacement was reduced by 45.8% by using full light-weight concrete. The finite element simulation results were in good agreement with the experimental results, which could provide reference for practical engineering design and application.

Influence characteristics of isolation piles on deformation of existing shallow foundation buildings under deep excavation

  • Liu, Xinrong;Liu, Peng;Zhou, Xiaohan;Wang, Linfeng;Zhong, Zuliang;Lou, Xihui;Chen, Tao;Zhang, Jilu
    • Geomechanics and Engineering
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    • 제31권1호
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    • pp.1-14
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    • 2022
  • Urban deep excavation will affect greatly on the deformation of adjacent existing buildings, especially those with shallow foundations. Isolation piles has been widely used in engineering to control the deformation of buildings adjacent to the excavation, but its applicability is still controversial. Based on a typical engineering, numerical calculation models were established and verified through monitoring data to study the influence characteristics of isolation piles on the deformation of existing shallow foundation buildings. Results reveal that adjacent buildings will increase building settlement δv and the deformation of diaphragm walls δh, while the isolation piles can effectively decrease these. The surface settlement curve is changed from "groove" type to "double groove" type. Sufficiently long isolation pile can effectively decrease δv, while short isolation piles will lead to a negative effect. When the building is within the range of the maximum settlement location P, maximum building rotation θm will increase with the pile length L and the relative position between isolation pile and building d/D increase (d is the distance between piles and diaphragm walls, D is the distance between buildings and diaphragm walls), instead, θm will decrease for buildings outside the location P, and the optimum was obtained when d/D=0.7.

표적 알파 치료의 현황 및 유용성에 대한 임상적 고찰 (Clinical Review of the Current Status and Utility of Targeted Alpha Therapy)

  • 최상규
    • 대한방사선기술학회지:방사선기술과학
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    • 제46권5호
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    • pp.379-394
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    • 2023
  • Targeted Alpha Therapy (TAT) is a new method of cancer treatment that protects normal tissues while selectively killing tumor cells using high cytotoxicity and short range of alpha particles, and target alpha therapy is a highly specific and effective cancer treatment strategy, and its potential has been proven through many clinical and experimental studies. This treatment method accurately delivers alpha particles by selecting specific molecules present in cancer tissue, which has an effective destruction and tumor suppression effect on cancer cells, and one of the main advantages of target alpha treatment is the physical properties of alpha particles. Alpha particles have a very high energy and short effective distance, interacting with target molecules in cancer tissues and having a fatal effect on cancer cells, which is known to cause DNA damage and cell death in cancer cells. TAT has shown positive results in preclinical and clinical studies for various types of cancers, especially those that resist or are unresponsive to existing treatments, but there are several challenges and limitations to overcome for successful clinical transition and application. These include the provision and production of suitable alpha radioisotopes, optimization of target vectors and delivery formulations, understanding and regulation of radiological effects, accurate dosage calculation and toxicity assessment. Future research should focus on developing new or improved isotopes, target vectors, transfer formulations, radiobiological models, combination strategies, imaging techniques, etc. for TAT. In addition, TAT has the potential to improve the quality of life and survival of cancer patients due to the possibility of a new treatment for overcoming cancer, and to this end, prospective research on more carcinomas and more diverse patient groups is needed.

Landfill gas-landfill degassing system and methods of using landfill gas at Sarajevo landfill

  • Dzevad Imamovic;Amra Serdarevic
    • Coupled systems mechanics
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    • 제12권6호
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    • pp.531-537
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    • 2023
  • Municipal solid waste landfills are unpredictable bioreactors which in cases of mishandling and bad supervision presents numerous risks. The key to municipal waste landfills is to approach them from the point of prevention of the possible consequences, which means using methods of organized waste disposal, and also utilizing landfill gas, as an unavoidable consequence with disposal of municipal solid waste with a high share of biodegradable organic matter. This paper presents an overview about problems of solid municipal waste management, type and composition of waste, and an overview of waste management condition. Further, the problem of landfill and landfill gasses is described with the calculation models of landfill production, as well as the use of the SWM GHG Calculator and LandGEM software on a specific example of gas production for the central zone at Sarajevo landfill "Smiljevici". Main focus of this thesis is the analysis of potentials of greenhouse gas emission reduction measures from the waste management. Overview of the best available techniques in waste management is presented as well as the methodology used for calculations. Scenarios of greenhouse gas emission reduction in waste management were defined so that emissions were calculated using the appropriate model. In the final section of the paper, its description of the problem of collection and utilization the landfill gas at the sanitary landfill "Smiljevici", and implementation of the system for landfill gas collection and solution suggestion for the gasification and exploitation of gas. Energy, environmental and economic benefits can be accomplished by utilizing municipal solid waste as fuel in industry and energy and moreover by utilizing energy generation from landfill gas, which this thesis emphasizes.

Generating Radiology Reports via Multi-feature Optimization Transformer

  • Rui Wang;Rong Hua
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • 제17권10호
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    • pp.2768-2787
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    • 2023
  • As an important research direction of the application of computer science in the medical field, the automatic generation technology of radiology report has attracted wide attention in the academic community. Because the proportion of normal regions in radiology images is much larger than that of abnormal regions, words describing diseases are often masked by other words, resulting in significant feature loss during the calculation process, which affects the quality of generated reports. In addition, the huge difference between visual features and semantic features causes traditional multi-modal fusion method to fail to generate long narrative structures consisting of multiple sentences, which are required for medical reports. To address these challenges, we propose a multi-feature optimization Transformer (MFOT) for generating radiology reports. In detail, a multi-dimensional mapping attention (MDMA) module is designed to encode the visual grid features from different dimensions to reduce the loss of primary features in the encoding process; a feature pre-fusion (FP) module is constructed to enhance the interaction ability between multi-modal features, so as to generate a reasonably structured radiology report; a detail enhanced attention (DEA) module is proposed to enhance the extraction and utilization of key features and reduce the loss of key features. In conclusion, we evaluate the performance of our proposed model against prevailing mainstream models by utilizing widely-recognized radiology report datasets, namely IU X-Ray and MIMIC-CXR. The experimental outcomes demonstrate that our model achieves SOTA performance on both datasets, compared with the base model, the average improvement of six key indicators is 19.9% and 18.0% respectively. These findings substantiate the efficacy of our model in the domain of automated radiology report generation.