• 한국추진공학회지
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• 제22권4호
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• pp.36-43
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• 2018

연소 중 고온, 고압, 고속의 연소가스가 작용하는 노즐조립체는 다양한 부품(목삽입재/내열재/구조체)이 접촉/접착의 형태로 조립되며, 유동(경계층 유동장)-열(기계/화학적 삭마, 숯 등 열반응, 열전달)-구조(마찰, 접촉, 접착, 동적거동 및 열응력)적 복합하중이 내부에 작용하며 복잡한 거동을 보이기 때문에 정확한 구조적 안전성을 계산하는데 한계가 있다. 본 연구는 연소시험 후 목삽입재 깨짐 현상이 발생한 노즐조립체에 대해 연소시간 중 열-구조적 거동분석을 해석적으로 수행하였다. 연소시간 중 시간별/위치별로 유동해석에서 계산된 내부압력과, 열반응을 고려한 열해석(Thermal Surface Reaction & Ablation Analysis)에서 계산된 노즐 표면의 삭마량 및 대류열전달계수가 구조해석의 경계/하중조건으로 부여된 후 열-변형 해석이 수행되는 연동해석(Co-simulation)기법을 사용하였다. 특히 구조해석 시각 부품별 경계면의 접착/접촉/마찰조건을 달리하며 연소시험 시 계측된 변형률값과 비교하여 가장 유사한 연소 중 거동분석 조건을 도출하였다.

• 대한치매학회지
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• 제17권4호
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• pp.148-155
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• 2018

Background and Purpose: Two conversion scales between the Mini-Mental State Examination (MMSE) and the Montreal Cognitive Assessment (MoCA) have been validated for Korean patients with Parkinson's disease. The aim of the present study was to validate these conversion scales for all patients with cognitive impairments regardless of dementia subtype. Methods: Medical records of 323 subjects who completed both MMSE and MoCA on the same day were retrospectively reviewed. Mean, median, and root mean squared error (RMSE) of the difference between true and equivalent MMSE scores were calculated. Intraclass correlation coefficients (ICCs) between true and equivalent MMSE scores were also calculated. The validity of MoCA-MMSE conversion scales was evaluated according to educational level (low educated: ${\leq}6$ years; high educated: ${\geq}7$ years) and subtypes of cognitive impairment. Results: The difference between true and equivalent MMSE scores had a median value of 0, a mean value of 0.19 according to the van Steenoven scale, a mean value of 0.57 according to the Lawton scale, RMSE value of 2.2 according to the van Steenoven scale, and RMSE value of 0.42 according to the Lawton scale. Additionally, ICCs between true and equivalent MMSE scores were 0.92 and 0.90 on van Steenovan and Lawton conversion scales, respectively. These results were maintained in subgroup analyses. Conclusions: Findings of the present study suggest that both van Steenovan and Lawton MoCA-MMSE conversion scales are applicable to transforming MoCA scores into MMSE scores in patients with cognitive impairments regardless of dementia subtype or educational level.

• Healthcare Informatics Research
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• 제24권4호
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• pp.359-370
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• 2018

Objectives: We assessed the public acceptance of a health information exchange (HIE) and examined factors that influenced the acceptance and associations among constructs of the Technology Acceptance Model (TAM). Methods: We collected data from a survey of 1,000 individuals in Korea, which was administered through a structured questionnaire. We assessed the validity and reliability of the survey instrument with exploratory factor analysis and Cronbach's alpha coefficients. We computed descriptive statistics to assess the acceptance and performed regression analyses with a structural equation model to estimate the magnitude and significance of influences among constructs of TAM. Results: Eighty-seven percent of the respondents were willing to use the technology, and the average level of agreement with the need for the technology was 4.16 on a 5-point Likert scale. The perception of ease of use of the technology significantly influenced perceptions of usefulness and attitudes about the need for HIE. Perceptions of usefulness influenced attitude and behavioral intention to use HIE, and attitude influenced intention. Age showed a wide range of influences throughout the model, and experience with offline-based information exchange and health status also showed noteworthy influences. Conclusions: The public acceptance of HIE was high, and influences posited by TAM were mostly confirmed by the study results. The study findings indicated a need for an education and communication strategy tailored by population age, health status, and prior experience with offline-based exchange to gain public buy-in for a successful introduction of the technology.

• 한국항행학회논문지
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• 제22권2호
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• pp.154-162
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• 2018

원전 주요계통의 전자카드에는 열화상태를 평가하기 위한 곱셈기가 필요하며, 이것은 두 개의 입력신호를 곱하는 기능을 가진 것으로서 실제 신호처리를 할 때 곱셈의 정확성을 기하기가 어렵다. 곱셈기 회로에서 중요한 것은 곱셈값이 정확해야 된다는 것과 곱셈의 선형성이 완벽해야 한다는 것이다. 본 논문에서는 연산증폭기와 트랜지스터의 특성을 이용하여 선형성이 우수한 곱셈기를 개발하여 본 논문에서 제시하여 정당성을 입증하려 하였다. 이와 같은 개발회로로서 정확한 곱셈과 곱셈의 우수한 선형성을 확보하기 위해 반도체의 비선형적인 요인을 제거하도록 노력하였다. 개발된 회로의 우수성을 입증하기 위해 개발된 회로에 적합한 각종 부품값을 부여하여 시뮬레이션으로서 곱셈연산을 수행하였다. 시뮬레이션 결과로서 단계별로 출력파형을 보였으며, 논리적인 분석치와 측정치를 비교분석하였다. 이 방법은 기존의 방법들에 비하여 곱셈결과와 선형성이 우수하다는 것을 확인하였다.

• 한국치위생학회지
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• 제22권2호
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• pp.133-142
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• 2022

Objectives: This study was conducted by clinical dentistry hygienists to develop knowledge measurement tools and evaluate knowledge necessary to cope with emergencies related to systemic diseases occurring in dentistry. Methods: Basic questions were developed on the six most frequently occurring diseases in the dental office: diabetes, syncope, respiratory disease, coronary artery disease, cerebrovascular disease, and epilepsy. Fifty-eight preliminary questions were composed in a survey format through expert validation. The survey was then conducted on 290 dental hygienists to verify the composition validity and reliability. Factor and reliability analyses were performed using the SPSS 23.0 program, and the correct answer rate for each question was calculated. Results: 49 items of a total of 13 factors were adopted as the final items for signs, symptoms, prevention and treatment of five diseases. The question with the highest percentage of correct answers for each question was "Slowly set up the unit chair when raising the patient"(97.9%) during the prevention of unconsciousness and question with the lowest correct answer rate was "soft substances such as cloth should be put in the mouth to prevent trauma while the seizure persists" (16.6%). Conclusions: A total of 49 questions have been developed as tools to measure the knowledge of dental hygienists' first aid related to systemic diseases and it is expected that related curriculum can be operated or evaluated by using them.

• International Journal of Industrial Entomology and Biomaterials
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• 제44권2호
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• pp.55-64
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• 2022

Bombyx shini Park & Sohn, 2002 (Lepidoptera: Bombycidae), which was listed as an endemic species in South Korea has recently been renamed as the East Asian silk moth Rotunda rotundapex Miyata & Kishida, 1990 (Lepidoptera: Bombycidae). In this study, we sequenced the complete mitochondrial genome (mitogenome) of the R. rotundapex to announce genomic characteristics and to clarify its validity with a new name. The 15,294-bp long complete mitogenome comprises a typical set of genes [13 protein-coding genes (PCGs), 2 rRNA genes, and 22 tRNA genes] and one major noncoding, A + T-rich region, with an arrangement identical to that observed in most lepidopteran mitogenomes. The A/T content of the whole mitogenome was 79.22%; however, it varied among the regions/genes as follows: A + T-rich region, 91.62%; srRNA, 84.67%; lrRNA, 83.01%; tRNAs, 81.43%; and PCGs, 77.46%. Phylogenetic analyses of 35 species in the Bombycoidea superfamily showed the sister relationship between the families Sphingidae and Bombycidae s. str., with the higher nodal support [bootstrap support (BS) = 78%]. The Saturniidae was placed as the sister to the two families, but the nodal support for this relationship was low (BS = 53%). Current R. rotundapex was placed together with previously reported con-species with the highest nodal support, forming a separate clade from Bombyx, validating that B. shini can have a new genus name, Rotunda. However, the Korean R. rotundapex showed a substantial sequence divergence at 5.28% to that originated from an individual of type locality Taiwan in 1,459-bp of COI sequences. Considering such a high sequence divergence an additional study, which includes morphological and DNA barcoding data from further extensive distributional range maybe is needed for further robust taxonomic conclusion.

• 대한한방부인과학회지
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• 제36권3호
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• pp.173-195
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• 2023

Objectives: To investigate and analyze the assessment indicators and tools used in clinical practice to assess Korean medicine (KM) treatment for infertility, and to establish a basis for assessment tools to diagnose and assess infertility. Methods: Relevant studies published until March 2023 were extracted from Pubmed, Research Information Sharing Service, and National Digital Science Library databases. Results: Sixty-four studies comprising 4,105 patients were included. We investigated pregnancy outcomes, and assessed pregnancy- and childbirth-related factors, overall health, reproductive health, and mental health. Pregnancy result was most common primary outcome. Ongoing pregnancy, stillbirth, miscarriage, and ectopic pregnancy rates were suggested as indicators of pregnancy and childbirth-related assessment. Overall health was most commonly assessed with Likert and Visual analogue scale (VAS). Among reproductive health variables, menstrual history was most frequently assessed. Moreover, indicators such as reproductive function, sexual intercourse, and gynecological disease were assessed. The Infertility Stress Scale and the Fertility Quality of Life tool (FertiQoL) were used to assess mental health. Conclusions: Subjective scales and objective assessment tools, such as the Likert scale and blood tests/ultrasonography, respectively, are used to assess KM infertility treatment. Inconsistent assessment tools make quantitative analyses more challenging. The development of a standardized mental and physical function assessment questionnaire with confirmed reliability and validity ensure the effectiveness of KM infertility treatment, and promote future studies on infertility treatment.

• 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.

• Steel and Composite Structures
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• 제47권1호
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• pp.51-69
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• 2023

In tied-arch bridges, a properly designed connection between the arch and the deck may become crucial, since the forces in the structure may be significantly reduced. This implies substantial material savings and, consequently, cheaper constructions. The introduction of the Nielsen cable arrangement (composed of V-shaped inclined hangers) in the last century was a milestone because it was able to reduce deflections and bending moments both in the arch and in the deck. So far, the Nielsen cable arrangement has proven to be successful in traditional vertical arch bridges. However, despite its advantages, it has not been widely applied to spatial arch bridges. Thus, this article analyses the difference between the structural behavior of spatial arch bridges with Nielsen-type cable arrangements with respect to those with classical vertical hanger configurations. The main goal is to verify whether the known effectiveness of the Nielsen cable arrangement for classical arch bridges is still preserved when applied to spatial arch bridges. In order to achieve this objective, and as the first part of our study, a set of different all-steel bridges composed of vertical and inclined arches with straight decks have been compared for both cable arrangements. As a major conclusion, for planar vertical arch bridges, the Nielsen-type cable arrangement is always the most effective. In addition, it also seems that, for spatial arch bridges composed of a straight deck and an inclined arch, it still keeps most of its effectiveness as long as the arch is moderately inclined.

• Structural Engineering and Mechanics
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• 제81권1호
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• pp.11-28
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• 2022

This paper considers the combination of cyclic and axial loads to investigate the hysteretic performance of H-section 6061-T6 aluminum alloy members. The hysteretic performance of aluminum alloy members is the basis for the seismic performance of aluminum alloy structures. Despite the prevalence of aluminum alloy reticulated shells structures worldwide, research into the seismic performance of aluminum alloy structures remains inadequate. To address this deficiency, we design and conduct cyclic axial load testing of three H-section members based on a reliable testing system. The influence of slenderness ratios and bending direction on the failure form, bearing capacity, and stiffness degradation of each member are analyzed. The experiment results show that overall buckling dominates the failure mechanism of all test members before local buckling occurs. As the load increases after overall buckling, the plasticity of the member develops, finally leading to local buckling and fracture failure. The results illustrate that the plasticity development of the local buckling position is the main reason for the stiffness degradation and failure of the member. Additionally, with the increase of the slenderness ratio, the energy-dissipation capacity and stiffness of the member decrease significantly. Simultaneously, a finite element model based on the Chaboche hybrid strengthening model is established according to the experiment, and the rationality of the constitutive model and validity of the finite element simulation method are verified. The parameter analysis of twenty-four members with different sections, slenderness ratios, bending directions, and boundary conditions are also carried out. Results show that the section size and boundary condition of the member have a significant influence on stiffness degradation and energy dissipation capacity. Based on the above, the appropriate material constitutive relationship and analysis method of H-section aluminum alloy members under cyclic loading are determined, providing a reference for the seismic design of aluminum alloy structures.