• Imaging Science in Dentistry
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• 제52권2호
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• pp.133-140
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• 2022

Purpose: The aim of this review was to systematically analyze the available literature on the correlation between the gray values (GVs) of cone-beam computed tomography (CBCT) and the Hounsfield units (HUs) of computed tomography (CT) for assessing bone mineral density. Materials and Methods: A literature search was carried out in PubMed, Cochrane Library, Google Scholar, Scopus, and LILACS for studies published through September 2021. In vitro, in vivo, and animal studies that analyzed the correlations GVs of CBCT and HUs of CT were included in this review. The review was prepared according to the PRISMA checklist for systematic reviews, and the risk of bias was assessed using the Quality Assessment of Diagnostic Accuracy Studies tool. A quantitative analysis was performed using a fixed-effects model. Results: The literature search identified a total of 5,955 studies, of which 14 studies were included for the qualitative analysis and 2 studies for the quantitative analysis. A positive correlation was observed between the GVs of CBCT and HUs of CT. Out of the 14 studies, 100% had low risks of bias for the domains of patient selection, index test, and reference standards, while 95% of studies had a low risk of bias for the domain of flow and timing. The fixed-effects meta-analysis performed for Pearson correlation coefficients between CBCT and CT showed a moderate positive correlation (r=0.669; 95% CI, 0.388 to 0.836; P<0.05). Conclusion: The available evidence showed a positive correlation between the GVs of CBCT and HUs of CT.

• 아태비즈니스연구
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• 제13권3호
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• pp.19-34
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• 2022

Purpose - The purpose of this study is to examine whether a psychological concept enhances healthcare users' service experience. Specifically, the study proposes and empirically examines a model of perceived control in which the user's sense of control is postulated as exerting positive influences upon his/her motivation, self-efficacy associated with his/her role as a patient, and satisfaction with his/her medical service experience. Methodology - Data were collected by a professional research company, using an online survey method. Participants of the study included adults nineteen years or older who had visited a medical service institute at least once during the previous one-year period. For the test of the research hypotheses, structural equation modeling using AMOS was used. Findings - Findings of this study denote a unique insight into the users' comprehension of medical service experiences and their behaviors. First, the concept of perceived control is identified as a factor that enhances the quality of individuals' medical service experiences. A sense of control directly influences medical users' self-efficacy to comply with doctor's recommendations, their motivation to comply with doctor's recommendations, and their satisfaction with the medical service experience. Second, one's perceived self-efficacy is found to exert positive influences upon both motivation and satisfaction. Third, one's motivation to comply with the doctor's recommendation is found to exert a positive influence upon one's satisfaction. Additionally, perceived control is found to exert an indirect influence upon medical service users' satisfaction through the mediation of both self-efficacy and motivation. Research Implications - The findings of the study support the notion that perception of control among medial service users enhances their service experience as patients. The main thrust of this study suggests that it is necessary for healthcare practitioners to consider implementing service encounter strategies that purposefully enhance the sense of control among their patients. The identification of significant inter-relationships among perceived control, motivation, self-efficacy, and satisfaction among medical service customers should also serve as a meaningful seed for further research pursuits.

• 한국공간구조학회논문집
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• 제22권3호
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• pp.33-40
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• 2022

Recently, cultural heritages in South Korea gain many interests of restoration and preservation from the government since many of that have been severely damaged during earthquakes. Many previous studies in both terms of experimental and analytical approaches have been done to examine structural behavior and decide appropriate methods of preservation. Being motivated by such researches, this research aims to investigate a religious stone pagoda dated back to the Goryeo Dynasty in Korea. The structure consists of a granite stone foundation and baked bricks, which resembles the shape of traditional pagodas. In order to examine the structural behavior of the pagoda, an analytical model is implemented using ANSYS, a comprehensive engineering simulation platform. For the time history analysis of the pagoda, several earthquake excitations are chosen and input to simulation modeling. Seismic response of the tower such as time domain, natural frequency, modal shapes and peak acceleration measured at each layer are presented and discussed. In addition, the amplification ratio of the tower is calculated from the accelerations of each layer to determine tower stability in accordance with Korean seismic design guide. The determination and evaluation of status and response of the brick tower by simulation analysis play an important role in the preservation of history as well as valuable architectural heritages in South Korea.

• 한국융합학회논문지
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• 제13권2호
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• pp.235-248
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• 2022

부모-자식 인터랙티브 게임 가구에 기초한 설계지표의 연구는 설계사들이 관련 상품의 설계의 장단점을 정량적으로 분석할 수 있게 하여 설계의 질을 관리하고 향상하는데 긍정적인 도움이 된다. 본 연구에서는 AHP와 TOPSIS를 결합하여 3가지 설계기준과 26가지 설계지수의 평가모델을 제안하였다. 각 지표에 대한 전문가들의 채점, 계산 및 일관성 테스트를 거쳐 각 설계지표의 가중치를 얻어낸 다음 각 지표의 중요정도에 따라 지표분류를 진행하였다. 분류결과 설계지표들을 8개의 중요지표와 11개의 보조지표, 7개의 일반지표로 분류하였다. 사례 연구에서는 TOPIS를 이용하였다. 세 종의 부모-자식 등반 게임 가구의 디자인 표본을 분석해 본 결과 세 표본의 상대 근접도는 최종적으로 각각 0.505, 0281 및 0.640 이였다. 연구를 통하여 AHP-TOPSIS 방법이 설계방안의 장단점을 과학적으로 효과적으로 분류 및 선별하고 관련 제품의 연구 및 개발에 참고를 제공할 수 있는 아주 유용한 방법이라는 것이 밝혀졌다.

• Smart Structures and Systems
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• 제29권1호
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• pp.181-193
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• 2022

Data-driven structural health monitoring (SHM) of civil infrastructure can be used to continuously assess the state of a structure, allowing preemptive safety measures to be carried out. Long-term monitoring of large-scale civil infrastructure often involves data-collection using a network of numerous sensors of various types. Malfunctioning sensors in the network are common, which can disrupt the condition assessment and even lead to false-negative indications of damage. The overwhelming size of the data collected renders manual approaches to ensure data quality intractable. The task of detecting and classifying an anomaly in the raw data is non-trivial. We propose an approach to automate this task, improving upon the previously developed technique of image-based pre-processing on one-dimensional (1D) data by enriching the features of the neural network input data with multiple channels. In particular, feature engineering is employed to convert the measured time histories into a 3-channel image comprised of (i) the time history, (ii) the spectrogram, and (iii) the probability density function representation of the signal. To demonstrate this approach, a CNN model is designed and trained on a dataset consisting of acceleration records of sensors installed on a long-span bridge, with the goal of fault detection and classification. The effect of imbalance in anomaly patterns observed is studied to better account for unseen test cases. The proposed framework achieves high overall accuracy and recall even when tested on an unseen dataset that is much larger than the samples used for training, offering a viable solution for implementation on full-scale structures where limited labeled-training data is available.

• Human Ecology Research
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• 제60권3호
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• pp.471-481
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• 2022

This study aimed at examining the mediation effects of depressive symptoms on the association between social activity participation and marital satisfaction among couples in later life. The study included 1,196 married couples aged 65 or above who participated in the 7th Korean Longitudinal Study of Aging in 2018. The study variables were husbands' and wives' social activity participation, marital satisfaction, and depressive symptoms. Covariates were individual age, education level, subjective health, couples' household income, and number of children. The Actor-Partner Interdependence Mediation Model (APIMeM) and bootstrapping techniques were used to test the significance of the mediating impacts of depressive symptoms based on the dyadic data structure. The results showed that for both husbands and wives, active participation in social activities had significant effects on increasing marital satisfaction through lowering depressive symptoms. However, only the participation of husbands in social activities was positively associated with their own marital satisfaction by reducing their own and their partner's depressive symptoms. These findings suggest that the active social participation of individuals salient for promoting the quality of marital relationships in later life, particularly for preventing their own and their spouse's depressive symptoms.

• Smart Structures and Systems
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• 제31권4호
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• pp.421-436
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• 2023

This paper presents a vibration displacement measurement and damage identification method for a space truss structure from its vibration videos. Features from Accelerated Segment Test (FAST) algorithm is combined with adaptive threshold strategy to detect the feature points of high quality within the Region of Interest (ROI), around each node of the truss structure. Then these points are tracked by Kanade-Lucas-Tomasi (KLT) algorithm along the video frame sequences to obtain the vibration displacement time histories. For some cases with the image plane not parallel to the truss structural plane, the scale factors cannot be applied directly. Therefore, these videos are processed with homography transformation. After scale factor adaptation, tracking results are expressed in physical units and compared with ground truth data. The main operational frequencies and the corresponding mode shapes are identified by using Subspace Stochastic Identification (SSI) from the obtained vibration displacement responses and compared with ground truth data. Structural damages are quantified by elemental stiffness reductions. A Bayesian inference-based objective function is constructed based on natural frequencies to identify the damage by model updating. The Success-History based Adaptive Differential Evolution with Linear Population Size Reduction (L-SHADE) is applied to minimise the objective function by tuning the damage parameter of each element. The locations and severities of damage in each case are then identified. The accuracy and effectiveness are verified by comparison of the identified results with the ground truth data.

• 한국지반공학회논문집
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• 제23권1호
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• pp.67-76
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• 2007

대변형을 고려한 유한요소법을 이용하여 flat DMT의 3차원 관입을 모사하였다. 상용 프로그램으로 널리 알려진 ABAQUS/Explicit를 이용하여 flat DMT의 3차원 관입 해석을 수행하였으며 관입 도중에 발생되는 큰 요소 변형을 해결하기 위하여 adaptive meshing 기법을 도입하였다. 해석 결과를 바탕으로, flat DMT 시험방법으로부터 얻어지는 3가지 지수 중에 하나인 수평응력지수($K_{D}$)와 지반 설계 정수인 비배수 전단강도 간의 관계를 살펴보았다. 그 결과 $K_{D}=2$ 정규압밀지반에서는 Marchetti(1980)가 제안한 경험적 상관관계식과, $K_{D}$가 2이상으로 모사되는 과압밀지반에서는 Kamei & Iwasaki(1995)가 제안한 경험적 상관관계식과 잘 일치하는 결과를 제공하였다.

• 한국컴퓨터정보학회논문지
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• 제14권5호
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• pp.167-174
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• 2009

데이터베이스의 의미는 '논리적으로 연관된 레코드나 파일의 모임'으로 방대한 자료를 효율적으로 관리하기 위해 많은 양의 자료를 처리하는 곳에서 널리 사용되고 있다. 이러한 데이터베이스를 생성하고, 관리하고, 사용자의 요구(Request)에 따라 응답(Response)을 보내는 프로그램들을 데이터베이스 관리시스템이라고 부른다. 본 연구에서는, 이와 같이 중요한 데이터베이스 소프트웨어 제품의 품질 수준을 파악할 수 있는 지표를 도출하여 지표산식을 정의하였다. 또한, 지표의 결과를 산출하기 위해 필요한 수집항목을 선정하며 수집과 분석을 통해 실질적으로 어떤 결함유형들이 주로 발생하고 있는지를 확인하였으며 데이터베이스 소프트웨어에 대한 시험 평가모델을 개발하여 시험 사례를 분석하였다.

• 인지과학
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• 제34권3호
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• pp.197-226
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• 2023

텍스트 생성요약은 자연어처리의 과업 중 하나로 긴 텍스트의 내용을 보존하면서 짧게 축약된 요약문을 생성한다. 생성요약 과업의 특성 상 본문의 핵심내용을 요약문에서 보존하는 것은 매우 중요하다. 기존의 생성요약 방법론은 정답요약과의 어휘 중첩도(Lexical-Overlap)를 기반으로 본문의 내용과 유창성을 측정했다. ROUGE는 생성요약 요약모델의 평가지표로 많이 사용하는 어휘 중첩도 기반의 평가지표이다. 생성요약 벤치마크에서 ROUGE가 49점대로 매우 높은 성능을 보임에도 불구하고, 생성한 요약문과 본문의 내용이 불일치하는 경우가 30% 가량 존재한다. 본 연구에서는 정답요약의 도움 없이 본문만을 활용해 생성요약 모델의 성능을 평가하는 방법론을 제안한다. 본 연구에서 제안한 평가점수를 AggreFACT의 라벨과 상관도 분석결과, 다음의 두 가지 경우 가장 높은 상관관계를 보였다. 첫 번째는 Transformer 구조의 인코더-디코더 구조에 대규모 사전학습을 진행한 BART와 PEGASUS 등을 생성요약 모델의 베이스라인으로 사용한 경우이고, 두 번째는 요약문 전체에 걸쳐 오류가 발생한 경우이다.