• Advances in concrete construction
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• 제10권4호
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• pp.301-310
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• 2020

The following paper concentrates on the objective of studying the influences of extent of duration and temperature on the Pozzolanic properties as well as reactivity of locally existing natural clay of Nai Gaj, district Dadu, Sindh Pakistan. The activation of the clay only occurs through heating when temperature in a furnace chamber reaches 600, 700 and 800oC for 1, 2 and 3 hours and at 900 and 1000℃ for 1 and 2 hours. Furthermore, the strength activity index (SAI) of advanced pozzolanic material happens to be identified through 20% cement replacement for different samples of calcined clay as per ASTM C-618. The compressive strength test of samples had been operated for 7 and 28-days curing afterwards. The maximum compressive strength had been seen in mix E in which cement was replaced with clay calcined at 700℃ for 1 hour that is 27.05 MPa that is 24.31% more than that of control mix. The results gathered from the SAI verdicts the optimal activation temperature is 700℃ within a one-hour time period. The SAI at a temperature of 700℃ with a one-hour duration at 28 days is 124.31% which happens to satisfy the requirements of the new Pozzolanic material, in order to be applied in mortar/concrete (i.e., 75%). The Energy- dispersive spectrometry (EDS) along with the X-ray diffraction (XRD) have been carried out in means of verifying whether there is silica content or amorphous silica present in metakaolin that has been developed. The findings gathered from the SAI were validated, as the analysis of XRD verified that there is in fact Pozzolanic activity of developed metakaolin. Additionally, based on observation, the activated metakaolin holds a significant influence on the increase in mortar's compressive strength.

• 한국항공우주학회지
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• 제45권3호
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• pp.217-225
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• 2017

본 연구는 국내 외 풍동기관들의 정적 공력측정 결과의 상호 비교검증 및 EFD-CFD 검증을 위해 수행되었다. 공군사관학교에서는 NRC 모델 기반 표준 동안정 모델을 제작하여 정적 특성을 측정하고, 풍동시험의 정확성 검증을 위하여 한국항공우주연구원 및 NRC에서 측정된 정적 공력측정 데이터를 상호 비교하였다. 또한 풍동시험 결과를 전산해석 결과와 비교하였으며 전산해석 유동장에서 분석된 오차원인을 확인하기 위하여 스트레이크 영향성을 검토하였다. 그 결과, EFD-CFD 간 피칭모멘트의 경향성이 상이하였으며, 스트레이크 효과는 크게 나타나지 않았다. 따라서 후방 지지대, 표준 동안정 모델의 흡입구에서 발생하는 와류에 의한 오차 분석과 전산해석의 격자해상도 재구성 등의 추가연구 진행이 필요한 것으로 판단된다.

• 보존과학회지
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• 제31권2호
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• pp.131-145
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• 2015

문화재 보존처리는 손상된 문화재의 수명을 연장하고 그 가치를 재조명하는 실질적 수단으로서 높이 평가 받고 있다. 그러나 보존처리 과정은 대부분 보존처리자의 경험과 기술에 의한 수작업에 의존하고 있어 이에 따르는 많은 시간과 노력이 요구된다. 최근에는 문화재의 재질 특성과 형상에 따라 보다 정확하고 손쉽게 보존처리를 진행할 수 있는 방법을 채용할 수 있게 되었다. 즉, 지금까지 수작업으로 이루어지는 보존처리과정을 3D 프린터를 이용하여 컴퓨터상에서 구현된 입체 형상 데이터를 실물로 출력하는 방법을 이용하는 것이다. 먼저 문화재의 결손 부분을 컴퓨터상의 데이터로 구축한 다음 3D 프린터로 출력하여 결손 부분을 손쉽게 성형 및 가공 과정을 거치는 것이다. 3D 프린터 적용결과 반복적인 출력 및 디지털데이터의 형태 및 수치 조정이 가능하였으며, 다양한 소재를 활용한 여러 가지 복원재료로 부터 시험출력을 통하여 문화재 복원의 완성도를 향상시킬 수 있었다. 본 연구에서 도자기 결손부분 복원을 위한 3D 프린터 적용 시험을 위하여 현대 재현품인 청자칠보무늬향로와 차륜식토기 2점을 인위적으로 파손시켰다. 복원결과 수작업에 비해 작업시간 단축 및 정확한 형태의 재현 등에서는 좋은 효과를 나타내었다. 반면 정밀한 접합 및 표면 질감을 생생하게 표현하기 위해서는 약간의 2차적인 수작업이 필요하였다.

• 한국환경보건학회지
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• 제47권1호
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• pp.64-77
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• 2021

Objective: Biological monitoring of trace elements in human blood samples has become an important indicator of the health environment. The purpose of this study was to detect and evaluate multiple metal items in blood samples based on ICP-MS, to perform comparative evaluation with the existing analysis method, and to develop and verify a new method. Methods: 100 μL of whole blood from 80 healthy subjects was used to analyze ten metals (Sb, tAs, Cd, Pb, Mn, Hg, Mo, Ni, Se, Tl) using ICP-MS. Verification of the analysis method included calculation of linearity, accuracy, precision and detection limits. In addition, a comparative test with the conventional graphite furnace atomic absorption spectroscopy (GF-AAS) method was performed. In the case of Pb, Cd, and Hg in whole blood, cross-analysis between Pb, Cd, and Hg analysis methods was performed to confirm the difference between the existing method and the new method (ICP-MS). Results: The coefficient of determination (R2) was 0.999 or higher in seven items and 0.995 or higher in three items. The Pb result showed that Pearson's correlation coefficient was very high at 0.983, and the intraclass correlation coefficient was 0.966. The Cd result showed that Pearson's correlation coefficient was 0.917 between the existing method and the new analysis concentration value. Its intraclass correlation coefficient was 0.960, and there was no significant difference between the two groups. Hg had a low correlation at 0.687, and the intraclass correlation coefficient was 0.761, which was lower than that of Pb and Cd. The intra-day and inter-day accuracy of Pd and Cd were satisfactory, but Hg did not meet the criteria for both accuracy and precision when compared with the conventional analysis method. Conclusion: This study can be meaningful in that it proposes a more efficient and feasible analysis method by verifying a blood heavy metal concentration experiment using multiple simultaneous analyses. All samples were processed and analyzed using the new ICP-MS. It was confirmed that the agreement between the two methods was very high, with the agreement between the current and new methods being 0.769 to 0.998. This study proposes an efficient simultaneous methodology capable of analyzing multiple elements with small samples. In the future, studies of various applications and the reliability of ICP-MS analysis methods are required, and research on the verification of accurate, precise, and continuous analysis methods is required.

• 유통과학연구
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• 제13권9호
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• pp.81-93
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• 2015

Purpose - "Showrooming" refers to the phenomenon where a shopper visits a store to see and compare products but makes the purchase online at a lower price. Surveys on showrooming activities at home and abroad indicate that a significant number of consumers pursue showrooming activities. The advent of "showroomers," who engage in buying activities, hovering both on and offline, while selectively choosing sales channels to suit their needs, is powerful enough to erode the borders between channels and bring about seismic changes in the distribution industry. However, surprisingly, there has been no in-depth discussion on showrooming. This study seeks to theoretically investigate what impact personal characteristics have on showrooming preferences and attitudes in a multi-channel environment. Specifically, assumptions have been made that price perception, perceived performance risk, and trust in online shopping not only have a direct impact on showrooming attitudes but also indirectly affect it through the means of contact motivation. Research design, data, and methodology - To test the hypotheses, this study conducted a survey of male and female shoppers, ages 20 through 40s, who live in metropolitan areas, and have actively showroomed fashion items in the last six months. A clothing item usually purchased after a careful decision-making process was chosen as the target product of the study. The survey was conducted between October and November 2014, using a professional survey service provider. A total of 200 surveys were collected, of which 198 were used for analysis. Conceptual model Structural Equation Modeling (SEM) and Amos 18.0 were employed for data analysis and model verification. In addition, following the confirmatory factor analysis and measurement model analysis, the theoretical model that corresponds to the research model was analyzed. Results - Analysis results show that price perception, perceived performance risk, and trust in online shopping have a statistically significant and positive (+) impact on showrooming attitudes. In addition, in terms of the indirect influence of price perception and perceived performance risk on showrooming attitudes through means of contact motivation, price perception had a statistically significant and positive impact on means of contact motivation, whereas perceived performance risk did not have a statistically significant impact on it, with the relevant hypothesis rejected. Conclusions - These analysis results imply that the ultimate goal of consumers is to maximize their shopping benefits by selectively and strategically taking advantage of different channels in a complementary manner. This study presents many implications for distributors to encourage a deep understanding of showrooming consumers who have complicated consumption behaviors and to build channel integration strategies. This study has limitations in theoretical and practical implications. Therefore, subsequent studies need to focus on verifying that showrooming activities are based on reasonable and planned decisions by applying the theory of reasoned or planned behavior. In addition, the scope of the study should expand to include web showrooming, where consumers conduct product research online and purchase offline.

• 대한후두음성언어의학회지
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• 제30권2호
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• pp.112-117
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• 2019

Background and Objectives The purpose of this study was to develop the differential diagnosis scale containing items from adductor spasmodic dysphonia (ADSD) to muscle tension dysphonia (MTD) and the determine clinical utility of newly developed items. Materials and Method The four parts of pitch, redirected phonation, automatic speech and voiced sound were selected for analyzing the characteristics of ADSD in the literature. One part of tense voiceless sound was developed according to the Korean manner of articulation. The content validity was evaluated based on 5 scales (1-5 point) analysis from 30 experts. One hundred patients (50 ADSD and 50 MTD) were recorded in reading a sentence and sustained phonation. The two speech language pathologist evaluated recorded voices through a blind test using 4 scales (0-3 point) for newly developed items. Results As a result of verifying the content validity of items with experts, it was identified that the differentiated items were valid with 4.2 out of 5. Through the differential diagnosis between two groups according to the items, the correlation between sub-domains and total scores was shown as higher than 0.710. The result of analyzing the reliability on each diagnosis domain was 0.840-0.893, which showed the internal consistency of items was great. Newly developed five parts of ADSD were significantly higher than those of MTD with strong correlation (p<0.01). The reliability among the evaluators was analyzed as high with 0.892. Conclusion In this study, the differential diagnosis scale of ADSD was revealed as having validity and reliability. It is considered that it will be useful for differentiating ADSD and MTD in the clinical field.

• 유통과학연구
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• 제10권12호
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• pp.35-43
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• 2012

Purpose - This study analyzes the effects of types of leadership on the employees of Italian restaurants, its efficacy, and organizational citizenship behavior, utilizing a causal assessment model. In this study, independent variables such as the type of leadership perceived in the manager or chef by an Italian restaurant's employees, and its efficacy were parameters, and the organizational citizenship behavior and organizational effectiveness were the variables representing the results in the hypothesis. The study aimed to draw implications by verifying the leadership via efficacy and the impact on organizational citizenship behavior of Italian restaurants. Research design, data, methodology - For the purpose of this analysis, specific questionnaire items were configured according to the theory and efficacy of the study. From a questionnaire used in organizational citizenship behavior comprising 22 questions, six were modified to suit the research purpose of this study. The configured questionnaire comprised 5 parts and 40 items. A Likert (Likert) 5-point scale was utilized to measure responses to the questionnaire items from the employees of an Italian restaurant in Seoul who participated in the survey. For data collection, 400 questionnaires were distributed, and 344 collected. Factor analysis and reliability verification were conducted using SPSS18.0 and AMOS18.0. A covariance structure analysis was conducted to test the research hypotheses. Results - Based on the results of the analyses, the summary and suggested implications of the research are as follows: The covariance structure analysis used to analyze the kind of effect transformational and transactional leadership styles in Italian restaurant employees had on self-efficacy, group-efficacy, and organizational citizenship behavior, indicated that among the characteristics of transformational leadership (such as, idealized influence, inspirational motivation, individual consideration, and intellectual stimulation), idealized influence and individual consideration had a positive influence on self-efficacy. Idealized influence, individual consideration, conditional reward, and management by exception also positively influenced self-efficacy and altruistic and conscientious behavior (organizational citizenship behavior). Conclusions - Results suggest that with regard to self-efficacy and group efficacy, managers in different departments and chefs should provide team members with a vision for the future, increase their confidence in their abilities, and build their trust in the organization. By evaluating employee performance and experiences, management can demonstrate leadership and encourage organizational citizenship behavior through enjoyable, voluntary participation. Transformational and transactional leadership is effective in group processes that include social-exchange relationships, self-efficacy and group efficacy, and organizational citizenship behavior. However, as this research study utilizes only self-reported data, it has several limitations, such as a vulnerability of errors caused by the various experiment types. A significant limitation of this study is the lack of potential for the duplication of results. The covariance structure analysis, however, provides complementation to limit the impact of errors from self-reporting studies. A future study can extend this research by utilizing different data collection methods.

• 대한기계학회논문집A
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• 제34권8호
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• pp.1067-1074
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• 2010

본 논문에서는, 운전조건에서의 저압최종단 블레이드에 대하여 약결합 유체-구조 연계해석기법을 이용한 해석이 수행되었다. 저압터빈 최종단에 대한 해석이전에 경계조건에 대한 검증을 위하여 15도 후퇴익과 NASA Rotor 37을 대상으로 예비해석이 수행되었다. 각각의 해석결과들을 기존 문헌들과 비교하였다. 15도 후퇴익에 대한 안정상태와 불안정상태에서 동적 FSI해석이 수행되었다. 해석결과 변위가 일정한 안정상태에 비하여 고속에서는 0.05 초 만에 발산하는 결과를 산출하였다. NASA Rotor 37의 정상상태 해석결과를 바탕으로 정적 동적 FSI 해석을 수행하여 뒷전의 변형크기에 대하여 정적 FSI 결과와 동적 FSI간의 차이가 있음을 확인하였다. 저압 최종단 블레이드의 형상측정 및 동특성시험을 바탕으로 해석모델을 생성하였다. 이를 바탕으로, 운전조건에서 저압최종단 블레이드에 대한 정적 유체-구조 연계해석을 성공적으로 수행하였다.

• 치위생과학회지
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• 제9권2호
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• pp.219-224
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• 2009

본 연구는 치위생과 학생들의 임상실습스트레스와 스트레스 대처방식, 신체화 경향간의 관계를 조사 연구하여 보다 효율적인 임상실습 지도를 위한 자료를 제공하기 위해 임상실습을 경험한 치위생과 재학생 268명을 대상으로 설문조사하여 SPSS WIN 12.0을 이용하여 분석한 결과 다음과 같은 결론을 얻었다. 1. 임상실습 만족도를 조사한 결과 '만족 한다'는 32.5%, '보통이다'는 42.2%, '불만족이다'는 25.4%로 나타났으며 임상실습 불만족 원인은 각각 '대인관계의 어려움'이 21.3%, 임상실습에 대비한 '학과교육의 불충분'이 29.8%, 실습병원에서의 '부적절한 업무수행'에 대한 불만이 23.4%로 학과 교육과정에 대한 불만이 가장 높았다. 2. 신체화 경향은 임상실습 스트레스와 양의 상관관계(.307, p < 0.01)를 전공만족도 및 임상실습 만족도와는 약한 음의 상관관계를 보였으며, 임상실습 스트레스 하위요인들과 신체화 경향간의 상관관계 분석에서는 대인관계 요인의 상관계수가 .331로 다른 하위 요인들에 비해 높게 나타났다(p < 0.01). 3. 스트레스 대처 방식에 따라 적극적 대처 그룹과 소극적 대처 그룹으로 나눈 후 신체화 경향에 대한 두 군간의 차이를 검증한 결과 적극적 대처 그룹에서 보다 낮은 신체화 점수 평균을 보여 소극적 대처 그룹과 통계적으로 유의미한 차이가 나타났다.

• 디지털융복합연구
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• 제15권12호
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• pp.47-57
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• 2017

본 연구는 상담자-내담자 간 인지사고 특성이 동일할 때와 상이할 때, 상담자에 대한 내담자의 친밀감수준, 공감수준, 소통 수준의 차이를 알아보고자 하였다. 이를 위하여 G소재 S사단의 또래상담병 70명을 대상으로 상담교육 6시간과 상담실습 4시간으로 총 10시간의 보수교육을 실시하였다. 상담실습에는 상담자로서 상담을 진행하는 시간과 내담자가 되어 최근 스트레스 사건에 대한 상담을 받는 시간으로 진행되었다. 사전에 모든 상담병은 APL 인지특성검사를 진행하였고, 두 가지 인지특성으로 구분하여, 2시간은 상담자와 동일한 인지특성을 가진 내담자와, 2시간은 상담자와 상이한 인지특성을 보이는 내담자와 상담을 진행하였다. 각 상담자와 내담자로서의 상담실습 종료 후, 상담자-내담자 동일성격, 상담자- 내담자 상이한 성격일 때 각 2회 친밀감수준, 공감수준, 소통수준을 자기보고로 평정하도록 하였다. 연구 결과, 상담자와 동일한 특성의 내담자와 상담을 할 때 상이한 특성의 내담자와 상담할 때보다 소통수준과 공감수준이 유의미하게 높게 나타났으며 상담의 친밀감 수준도 유의미하게 높았다. 본 연구결과는 상담의 효과성을 높이기 위해서는 상담자와 내담자의 인지적 특성을 고려한 상담 배치 또는 상담자의 자기이해 및 내담자의 특성을 고려한 상담계획의 중요성을 시사한다.