• Title/Summary/Keyword: generalizability

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Deep Learning-Based Computed Tomography Image Standardization to Improve Generalizability of Deep Learning-Based Hepatic Segmentation

  • Seul Bi Lee;Youngtaek Hong;Yeon Jin Cho;Dawun Jeong;Jina Lee;Soon Ho Yoon;Seunghyun Lee;Young Hun Choi;Jung-Eun Cheon
    • Korean Journal of Radiology
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    • v.24 no.4
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    • pp.294-304
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    • 2023
  • Objective: We aimed to investigate whether image standardization using deep learning-based computed tomography (CT) image conversion would improve the performance of deep learning-based automated hepatic segmentation across various reconstruction methods. Materials and Methods: We collected contrast-enhanced dual-energy CT of the abdomen that was obtained using various reconstruction methods, including filtered back projection, iterative reconstruction, optimum contrast, and monoenergetic images with 40, 60, and 80 keV. A deep learning based image conversion algorithm was developed to standardize the CT images using 142 CT examinations (128 for training and 14 for tuning). A separate set of 43 CT examinations from 42 patients (mean age, 10.1 years) was used as the test data. A commercial software program (MEDIP PRO v2.0.0.0, MEDICALIP Co. Ltd.) based on 2D U-NET was used to create liver segmentation masks with liver volume. The original 80 keV images were used as the ground truth. We used the paired t-test to compare the segmentation performance in the Dice similarity coefficient (DSC) and difference ratio of the liver volume relative to the ground truth volume before and after image standardization. The concordance correlation coefficient (CCC) was used to assess the agreement between the segmented liver volume and ground-truth volume. Results: The original CT images showed variable and poor segmentation performances. The standardized images achieved significantly higher DSCs for liver segmentation than the original images (DSC [original, 5.40%-91.27%] vs. [standardized, 93.16%-96.74%], all P < 0.001). The difference ratio of liver volume also decreased significantly after image conversion (original, 9.84%-91.37% vs. standardized, 1.99%-4.41%). In all protocols, CCCs improved after image conversion (original, -0.006-0.964 vs. standardized, 0.990-0.998). Conclusion: Deep learning-based CT image standardization can improve the performance of automated hepatic segmentation using CT images reconstructed using various methods. Deep learning-based CT image conversion may have the potential to improve the generalizability of the segmentation network.

A Critical Review of Health Behavior Studies of Adolescents Conducted in Korea (청소년 건강행위에 대한 국내연구동향)

  • Park, Nam-Hee;Lee, Hae-Jung
    • Research in Community and Public Health Nursing
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    • v.13 no.1
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    • pp.98-114
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    • 2002
  • Purpose: This review examined literature relevant to adolescent's health behavior in order to identify key behaviors and factors related to health behaviors for targeting health promotion interventions. Method: A critical review of 29 research articles was carried out using the guidelines suggested by Cooper. Result: The majority of the studies were descriptive and cross-sectional. Generally. the study includes sub-dimensions such as general hygiene and daily life habit, safety and accident prevention, nutrition and eating (tobacco, drinking), exercise, mental health and stress management, health duty (drug, health examination, disease prevention). Factors highly related to health behaviors were age, living areas, economic status, parent health behaviors, parent health concern, social support, friends influence, self-efficacy, self-esteem, locus of control, and the perceived health status. Sex, parent education and health knowledge were not related to health behaviors of adolescents. Conclusion: Several conceptual and methodological problems were identified in the studies review, such as restricted conceptualization of health behaviors and sampling issues which limit the generalizability of the study outcomes. Further research is needed to enhance the concept clarification and generalizablity of the study results.

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Detecting Deception Using Neuroscience : A Review on Lie Detection Using Functional Magnetic Resonance Imaging (거짓 탐지와 뇌과학 : 기능적 자기공명영상을 활용한 거짓 탐지)

  • Choi, Yera;Kim, Sangjoon;Do, Hyein;Shin, Kyung-Shik;Kim, Jieun E.
    • Korean Journal of Biological Psychiatry
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    • v.22 no.3
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    • pp.109-112
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    • 2015
  • Since the early 2000s, there has been a continued interest in lie detection using functional magnetic resonance imaging (fMRI) in neuroscience and forensic sciences, as well as in newly emerging fields including neuroethics and neurolaw. Related fMRI studies have revealed converging evidence that brain regions including the prefrontal cortex, anterior cingulate cortex, parietal cortex, and anterior insula are associated with deceptive behavior. However, fMRI-based lie detection has thus far not been generally accepted as evidence in court, as methodological shortcomings, generalizability issues, and ethical and legal concerns are yet to be resolved. In the present review, we aim to illustrate these achievements and limitations of fMRI-based lie detection.

The Effect of the Products' Review on Consumers' Response

  • Feng, Zhou
    • The Journal of Industrial Distribution & Business
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    • v.7 no.2
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    • pp.13-20
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    • 2016
  • Purpose - The purpose of this research is to discover whether the presence of the product average rating introduces biases or change the way people perceive information. We posit that review's overall rating has a predisposition effect on consumers' perception towards detailed review information. Research design, data, and methodology - To test these hypotheses, we conducted an empirical study on a real-world setting of online shopping platform. We choose the Amazon website to test our results. The data we use were collected by the Stanford Network Analysis Project1 (McAuley et al., 2013). Results - With a dataset containing reviews of seven product categories from amazon.com., our findings could possess more generalizability as they are produced on the typical and influential online market. Second, as our research provides alternative views of consumers' shopping behavior, it is better to test our hypotheses by data from the same source. Conclusions - Our study reveals the impact of the collective rating presence on consumers' diagnosticity perception and sheds light upon some of the conflictive results in prior studies. Our research generates implications to both theories and business practices, and suggests future directions for the research question.

Reconstruction of a near-surface tornado wind field from observed building damage

  • Luo, Jianjun;Liang, Daan;Weiss, Christopher
    • Wind and Structures
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    • v.20 no.3
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    • pp.389-404
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    • 2015
  • In this study, residential building damage states observed from a post-tornado damage survey in Joplin after a 2011 EF 5 tornado were used to reconstruct the near-surface wind field. It was based on well-studied relationships between Degrees of Damage (DOD) of building and wind speeds in the Enhanced Fujita (EF) scale. A total of 4,166 one- or two-family residences (FR12) located in the study area were selected and their DODs were recorded. Then, the wind speeds were estimated with the EF scale. The peak wind speed profile estimated from damage of buildings was used to fit a translating analytical vortex model. Agreement between simulated peak wind speeds and observed damages confirms the feasibility of using post-tornado damage surveys for reconstructing the near-surface wind field. In addition to peak wind speeds, the model can create the time history of wind speed and direction at any given point, offering opportunity to better understand tornado parameters and wind field structures. Future work could extend the method to tornadoes of different characteristics and therefore improve model's generalizability.

The Role of Structural Holes in Uncertain Environments in Channel Relationships

  • Kim, Min-Jung
    • Journal of Distribution Science
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    • v.16 no.6
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    • pp.25-35
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    • 2018
  • Purpose - Although marketing networks are crucial competitive advantage in terms of firm's new information and resource acquisition ability, their impact on new product development performance remains vague, especially under environmental uncertainty. The principal objective of this research is to provide a better understanding of effects of technological uncertainty and volume uncertainty on first tier supplier's perceived performance of new product development under conditions reflecting varying levels of structural holes. Specifically, this research examines the moderating effect of structural holes on the relationship between environmental uncertainty and new product development performance. Research design, data, and methodology - To test the hypotheses, a questionnaire survey was conducted with a Korean engineering firm's major first-tier suppliers in the context of internal network entities, manufacturer-supplier-subsupplier relationships, and to verify the proposed hypotheses, structural equation modeling was established. Construct measures were based on existing measures and previous research. Results - The survey results indicate that technological uncertainty and volume uncertainty differentially affect NPD performance under conditions of high and low structural holes. Conclusions - This study offer some theoretical and practical implications among distribution channel members, especially, this study suggests that interfirm networks have critical competitive advantage in uncertain environments. The distinctiveness of engineering industry might limit the generalizability of the results. Thus, future research should consider a wider range of industries.

The relationship among adult attachment types, love styles and dating of single people (성인 애착유형과 미혼남녀의 사랑유형 및 이성교제의 관계)

  • Noh, Eu-Jin;Park, Jung-Yun;Kim, Yang-Hee
    • Journal of the Korean Home Economics Association
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    • v.44 no.12
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    • pp.31-42
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    • 2006
  • The purpose of this study was to investigate the correlation among parental bonding, attachment styles, love styles and satisfaction in dating and their effects on other variables. The main findings of the study were as follows 1)The stronger the relationship with one's parents in infancy, the higher the possibility to forge secure attachment. 2)There was a significant correlation between attachment styles and love styles. 3)There was a significant correlation between attachment styles and dating satisfaction. 4)There were meaningful differences on dating satisfaction and duration among different love types. This study showed the importance of forging secure attachment between parents and children, and found related variables that can affect dating satisfaction and duration. However, the study results were based on a limited group of people, which limits the generalizability of the results to the general public. Follow-up studies that cover a wide range of age groups and related variables are necessary.

Development of Medical Service Scale (의료서비스 척도 개발)

  • Nam, Seung-Kyu;Woo, Hoon-Shik;Kim, Young-Il;Cho, Chung-Sik
    • Journal of Haehwa Medicine
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    • v.22 no.2
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    • pp.143-154
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    • 2014
  • Objective : The purpose of this study is to establish a concept called as 'medical service' newly and to develop an reliable and valid scale that measures medical service. Methods : In order to accomplish these objectives, both conceptual study and empirical study were performed. In a conceptual study, 5 core factors(doctor, medical team, medical facilities, medical process, and hospital) and 24 sub factors were extracted with assistant by 7 experts, based on antecedent studies about components of medical service. In an empirical study, data was taken from 244 adults living in Seoul and Daejeon with the conceptually founded medical service scale. Results : Results of empirical study showed reliability and validity of the medical service scale. Internal consistency coefficient showed high score of .97 and, in accordance with the conceptual study, "medical treatment factor", "appearance factor", "personal factor", "trust factor" and "dissatisfaction factor" were extracted from the data as the five main factors. Conclusions : Finally, limitations of this study and directions for further studies are discussed. Acknowledgement : This work was supported by the Daejeon University Research Grant.

A Study on the Validity and Reliability of Performance Assessment in Home Economics (가정과 수행평가의 타당성과 신뢰성 연구 - 경남 농촌지역의 소인수 학급을 대상으로 -)

  • 윤성희;유태명
    • Journal of the Korean Home Economics Association
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    • v.39 no.10
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    • pp.169-186
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    • 2001
  • The purpose of the study was to verify validity and reliability of performance assessment in home economics by applying performance assessment tools developed by Korean Curriculum Assessment Institute and by the researcher to a class of 17 high school female students in a rural area. For the purpose of this study, the research question was formulated and addressed:“How are the validity and reliability of performance assessment in home economics\ulcorner” The results of the study were as follows. 1. The results of testing validity a. Thirteen high school home economics teachers, whose average teaching years is ten years verified high validity in the contents of performance assessment. b. In the validity of the items that is verified being based on the scores of high school entrance examination of 2000 school year, the essay type showed its characteristics as performance assessment. c. The generalizability among assessment methods was not high. 2. The results of testing reliability Both Cronbach's $\alpha$, inter-item reliability of the assessment tools used in the research, and reliability among the raters were high. But reliability among the tasks was relatively low. This study proposed that the diverse performance methods, the increasing number of assessment, the explicit assessment criterion, and scoring criterion are needed to satisfying validity and reliability of performance assessment.

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The Effect of Essential Online Elements on Consumer Purchase Intention: Insights from a Taobao Perspective

  • Feng, Zhou;Lee, Un-Kon
    • Journal of Distribution Science
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    • v.13 no.5
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    • pp.15-22
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    • 2015
  • Purpose - Transparency, seller reputation, and website security are considered to be important factors that influence online customer purchasing decisions in China. This paper empirically examines the relative influence of Taobao.com on customers' online purchasing decisions. Research design, data, and methodology - We perform structural equation analysis, with a sample of 306 observations. The data comes from consumers' real transaction experiences from a specific website. This gives the results of our study more generalizability than studies using subjects who are not asked to engage in real transactions. Results - The results of this study reveal that perceived security and perceived reputation are critical factors affecting consumer trust and perceived transparency is most closely associated with purchase intention. Conclusions - The findings suggest that perceived transparency plays a significant role in increasing online consumer's purchase intention. The knowledge of the relative impacts of these factors and their roles in the customer transaction experience will be useful in developing customized sales strategies. The results of this study reveal that perceived transparency exerts a stronger effect than perceived reputation on consumer purchase intentions.