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        검색결과 123

        1.
        2024.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 논문에서는 조선 후기의 대표적인 전통목구조인 수원 화령전 운한각의 구조성능을 평가하였다. 운한각의 가구구성 방식에 맞추 어 3차원 구조해석 소프트웨어인 midas Gen으로 해석모델을 정교하게 구축하였다. 정적해석으로 주요 구조부재의 안전성과 사용성 을 평가하였고, 고유치해석으로 동적거동특성을 평가하였다. 대부분의 부재가 안전성 및 사용성 기준을 여유 있게 만족하고 있으나, 외목도리에서 휨응력비가 기준을 20.7% 초과하고 있어 이 부재에 대해서는 장기적인 모니터링이 필요하다고 사료된다. 운한각의 고 유주기는 1.079초로 비슷한 규모의 전통목구조보다 약간 긴 편이며, 특히 후면 화방벽의 영향으로 2차모드에서 비틀림이 발생한 것으 로 분석된다.
        4,000원
        2.
        2023.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        기존의 연령별 얼굴정서 인식 비교 연구에서는 정서별로 연령 간에 어떤 차이가 있는지 밝혔다. 이에 Kim(2021) 연구에서는 개별 정서가 아닌 정서공간에서 표상된 정서를 연령 간 비교하였다는 점에서 의의가 있으나, 기술적 (descriptive) 비교만 시행하였을 뿐, 통계적 유의미 검증을 하지 않았다는 한계가 있다. 본 연구에서는 표상 유사성 분석(representational similarity analysis) 방법을 통해 연령간 실제 데이터 및 정서 모델 유사성행렬을 직접적으로 비교하였다. 또한 개인차 다차원척도법(individual differences multidimensional scaling)을 통해 연령간 정서 차원에 대한 비중을 비교하였다. 그 결과 실제 데이터 비교에서 노년 집단은 청년 및 중년 집단과 가장 유사하지 않았으며, 쾌불쾌 차원이 포함된 정서 모델과의 유사성 비교에서도 가장 유사하지 않았다. 또한 노년 집단은 각성 차원에 대한 비중이 청년 및 중년 집단과 유사하지 않음이 발견되었다. 본 연구는 실제 데이터, 정서 모델, 그리고 정서 차원 비중이라는 세 가지 측정치에 대해 노년 집단과 청년 및 중년 집단과의 차이를 통계적으로 검증하였다는 점에서 의의가 있다.
        4,000원
        4.
        2021.11 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Background: Considering the kinetic chain of the lower extremity, a pronated foot position (PFP) can affect malalignment of the lower extremity, such as a dynamic knee valgus (DKV). Although the DKV during several single-leg movement tests has been investigated, no studies have compared the differences in DKV during a single-leg step down (SLSD) between subjects with and without PFP. Objects: The purpose of this study was to compare the DKV during SLSD between subjects with and without PFP. Methods: Twelve subjects with PFP (9 men, 3 women) and 15 subjects without PFP (12 men, 3 women) participated in this study. To calculate the DKV, frontal plane projection angle (FPPA), knee-in distance (KID), and hip-out distance (HOD) during SLSD were analyzed by twodimensional video analysis software (Kinovea). Results: The FPPA was significantly lower in PFP group, compared with control group (166.4° ± 7.5° and 174.5° ± 5.5°, p < 0.05). Also, the KID was significantly greater in PFP group, compared with control group (12.7 ± 3.9 cm and 7.3 ± 2.4 cm, p < 0.05). However, the HOD not significantly differed between two groups (12.7 ± 1.7 cm and 11.4 ± 2.5 cm, p > 0.05). Conclusion: The PFP is associated with lower FPPA and greater KID. When assess the DKV during SLSD, the PFP should be considered as a crucial factor for occurrence of DKV.
        4,000원
        5.
        2021.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 논문에서는 정전기 흡착패드를 구성하는 곡면형 전극의 기하학적 엄밀성을 고려하기 위해 정전기 문제에 대하여 CAD에서 사 용하는 NURBS 기저함수를 직접 사용하는 아이소-지오메트릭 해석 기법을 도입하였다. 정전기 흡착력을 곡선 접촉면에서 구하는데 법선 벡터의 영향이 크므로 엄밀한 기하형상을 고려하는 아이소-지오메트릭 해석이 강점을 갖는다. 수치 예제를 통해 곡면과 평면에서 반복 구조의 유무에 따른 파라메터 연구를 수행하여 곡면형 전극의 흡착력이 좋은 성능을 가짐을 보였다. 정전기 흡착력의 성분을 분석하였을 때 정전기 흡착력의 차이는 법선 성분 전기장의 증가로 인한 것으로 파악되었다. 결론적으로 곡면형 전극에서도 전극 사이 거리가 가까워지는 아래로 볼록인 경우가 가장 성능이 좋고, 위로 볼록인 경우에는 성능이 가장 낮음을 보였다.
        4,000원
        6.
        2020.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Bilateral profound friendship between China and Pakistan and the "all-weather strategic partnership" have given great support to mutual cooperation. China and Pakistan are moving forward to the goal of "economic corridor construction as the center, Gwadar port, transport infrastructure, energy and industrial cooperation as the points to form the ‘1+4’ economic cooperation and common development". However, the relationship between the two countries is also facing some challenges in the process of sustainable development, among which the populist in Pakistan is gradually emerging. If left unchecked, it may lead to a great threat to CPEC and other cooperation. Therefore, strengthening basic research on populism in Pakistan is of great significance for enhancing the all-weather strategic cooperative partnership and ensuring the smooth implementation of the CPEC. After reviewing the current research status and deficiencies of populism theory, this paper analyzes populism from the dimensions of social classes, religions and regions, so as to deeply understand the breeding source of populism. From the perspective of class, populism in Pakistan has distinct characteristics of class antagonism. From a religious perspective, there is a deeply rooted political psychology among the Pakistani people. From a regional perspective, the traditional social structure of Islam in Pakistan determines that the loyalty of individuals to religion, family and a smaller region is greater than the loyalty to the nation state.
        5,800원
        7.
        2020.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In order to design a diesel engine system and predict its performance, it is necessary to analyze the gas flow of the intake and exhaust system. A gas flow analysis in three-dimensional (3D) format needs a high-resolution workstation and enormous time for analysis. Therefore, the method of characteristics (MOC) was used for a gas flow analysis with a fast calculation time and a low-resolution workstation. An experiment was conducted on a single cylinder diesel engine to measure pressure in cylinder, intake pipe and exhaust pipe. The one-dimensional (1D) gas flow was analyzed under the same conditions as the experiment. The engine speed, valve timing and compression ratio were the same conditions and the intake pressure was inputted as the experimental results. Bent pipe such as an exhaust port that cannot be realized in 1D was omitted. As results of validation, the cylinder pressure showed accuracy, but the exhaust pipe pressure exhibited inaccuracy. This is considered as an error caused by the failure to implement a bent pipe such as an exhaust port. When analyzed in 3D, calculation time required 61 hours more based on a model of this study. In the future, we intend to implement a bent pipe that cannot be realized in 1D using 3D and prepare a method to supplement reliability by using 1D-3D coupling.
        4,000원
        8.
        2020.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The flow analysis of two dimensional transient flow over the obstacles with rectangular cross sections was performed. And 190 velocity distributions for each aspect ratio were imaged to provide input data for convolutional neural network learning. The classification and regression methods were used in estimating the aspect ratio from given velocity distributions. As a result the classification method was more exact than the regression method. But both the classification and regression methods gave relatively accurate prediction of the defined aspect ratio judging from the imaged velocity distributions. This confirms that the deep learning technique is applicable to the flow analysis.
        4,000원
        9.
        2019.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Background: Although magnetic resonance imaging is accurate, it is expensive to measure the movement of temporomandibular joint. The three-dimensional (3D) motion analysis system is an inexpensive measurement tool. Objects: This study examined the reliability of quantifying the mouth opening and lateral mandibular shift and differences between individuals with and without temporomandibular disorder (TMD) using the hygienic method of surface markers on the skin with 3D ultrasound-based motion analysis. Methods: This study included 24 subjects (12 with and 12 without TMD). Temporomandibular joint motion during mouth opening was recorded using two surface markers with 3D ultrasound-based motion analysis. An intraclass correlation coefficient [ICC (3,k)] was used to confirm the intrarater reliability of quantifying kinematic temporomandibular joint motion, and an independent t-test was used to evaluate differences in maximal mouth opening and lateral mandibular shift between the two groups. Results: Assessment of mouth opening and lateral mandibular shift showed excellent test–retest reliability with low standard error of measurement. The lateral mandibular shift and opening-lateral mandibular shift ratio were significantly increased in the TMD group during maximum mouth opening (p<.05). However, no significant difference in maximal mouth opening was observed between the groups with and without TMD (p>.05). Conclusion: This hygienic and simple surface marker method can be used to quantify the mouth opening and lateral mandibular shift at the end-range of mouth opening. The TMD group showed an increased lateral mandibular shift movement at the end-range of mouth opening. The lateral mandibular shift movement can be regarded as a symptom in the diagnosis and treatment of TMD.
        4,000원
        11.
        2018.11 구독 인증기관·개인회원 무료
        In porcine production, porcine litter size is a quantitative trait and its heritability is especially low. So it is necessary to identify porcine reproductive gene and protein. The establishment of pregnancy requires performance of a receptive endometrium and ovary. The endometrium and ovary go through transformations in response to physiological changes initiated by local factors including ovarian hormones and uterine environment that make it for possible pregnancy. The endometrium and ovary secrete a wide array of growth factors, cytokines and proteins. Based on these background, we analyzed the endometrial tissue protein of porcine and would find out biomarker proteins related to porcine litter size. We sorted the two groups according to litter size of porcine: a small litter size group (SLSG) (n=2) and a large litter size group (LLSG) (n=2). The porcine endometrial tissue and ovary samples were preprocessed for proteomic analysis. In order to comparison, samples of each 2mg endometrium protein and ovary protein were separated form pI and molecular weight in the same conditions by applying a pH 3.0-10.0 IPG gels for the first dimension and then 8-16% SDS-PAGE gel for the second dimension. After proteins were visualized by staining with Commassie brilliant blue (CBB), image analysis was performed with Image Master detect variations in protein spots between large litter size group and small litter size group endometrium. And then differential proteins were identified using MALDI-TOF analysis. The master images of 2-DE gel images obtained from 2mg samples of large litter size group and small litter size group endometrial proteins at pH 3.0-10.0 revealed more than 400 protein spots in pH 3.0-10.0 range. When we analyzed the levels of expression of proteins that protein spots appeared more than 1.5-fold difference in endometrial tissue from porcine. In comparison of SLSG(small litter size group) with LLSG(large litter size group), a total of 18 protein spots differentially expressed on porcine endometrial tissue 2-DE gels, among which 9 spots were up-regulated proteins as retinol dehydrogenase 16-like isoform 1, Acrosin-binding protein, alpha-N-acetylgalactosaminidase. phosphoglycerate kinase 2, Acrosin-binding protein in LLSG. And 8 spots were up-regulated proteins as phosphoglycerate kinase 2, prenylcysteine oxidase in SLSG.
        12.
        2018.11 구독 인증기관·개인회원 무료
        Importance of the in vitro model of tissues or organs is now evident in tissue engineering and cell biology research. Till now, two-dimensional culture systems have been using for in vitro cell culture, and have contributed to cell function studies despite their limitations. Three-dimensional (3D) culture has been utilized in cell biology research because it appears to mimic morphology and physiology of cells in living tissues and organs, unlike conventional monolayer cell culture. In our laboratory, we are developing 3D culture systems of bovine endometrial cells as a tool for the analysis of uterine endometrial functions. Among them, this lecture introduces spheroid culture and Matrigel culture. 1. Spheroid culture; Spheroids are a spherical mass composed of cells and extracellular matrices (ECMs). We have regenerated multicellular spheroids composed of bovine endometrial stromal and epithelial cells using ascorbate (1). Expression of MMPs, which are key enzymes for the tissue remodeling of the endometrium, were analyzed using the spheroid. E2, P4 and type-I IFN did not affect the gene expression of MMPs in the spheroid. However, treatment of type-I IFN increased the clearance of MMPs in the supernatant. These results suggest that IFN indirectly regulates endometrial tissue remodeling through clearance of MMPs. 2. Matrigel culture; It is reported that cells form lumens automatically by culturing cells in Matrigel (2). Matrigel is a solubilized basement membrane extracted derived from EHS mouse sarcoma cells. The bovine endometrial epithelial cells cultured in 15% Matrigel formed a circular or elliptical gland-like structure. Gene expressions of glandular epithelial specific factors (FOXA2, SERPINA14 and GRP) were significantly high in the Matrigel, compared to the monolayer cultured cells, except FOXA2. Further, SERPINA14 expression was affected by neither P4 nor IFN. However, when epithelial cells in Matrigel were co-culture with stromal cells, SERPINA14 expression increased significantly in the treatment of both P4 and IFN. These results suggest that bovine endometrial epithelial cells cultured in Matrigel show properties similar to the glandular epithelial cells in vivo, and regulated by the factors produced by the stromal cells. Finally, by using these 3D culture systems, it becomes possible to clarify not only factors regulating embryo elongation and implantation but also regulation of their expression. It will be able to reveal the mechanism of the embryo elongation and implantation to contribute to the improvement of the embryo transplantation technique. (1) Yamauchi N, Yamada O, Takahashi T, Imai K, Sato T, Ito A, Hashizume K. A three-dimensional cell culture model for bovine endometrium: regeneration of a multicellular spheroid using ascorbate. Placenta. 2003; 24(2-3):258-69. (2) Eritja N, Llobet D, Domingo M, Santacana M, Yeramian A, Matias-Guiu X, Dolcet X. A novel three-dimensional culture system of polarized epithelial cells to study endometrial carcinogenesis. Am J Pathol 2010; 176:2722-2731.
        13.
        2018.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        범용유한요소프로그램인 Abaqus의 확장유한요소법(XFEM)의 사용성 검증을 위하여 2차원 모델에 적용하여 수치해석을 수행하였다. 기존의 연구에 많이 사용되었던 응집요소(cohesive element) 모델은 균열 경로를 예측하고 요소를 삽입하여야 하는 단점 때문에 실제 균열을 모사하는데 한계가 있다. 이러한 이유로 응력의 방향성 및 특이성을 바탕으로 균열의 경로를 예측하는 확장유한요소법(XFEM)이 균열 해석에 있어서 더 발전된 방법으로 이용되어 왔다. 이번 연구에서는 균열의 경로가 자명한 2차원 모델에 사용하여 응집요소해석과 XFEM에 응집요소의 물성을 적용한 해석을 비교하고 XFEM 적용의 타당성을 확인하였다. 수치해석으로 균열 발생 직전의 응력분포 및 응력 특이성을 확인하고 실제 균열 발생경로와의 비교를 한다. 본 연구를 바탕으로 몇 가지의 한계를 극복하면 실제 복잡한 모델의 실제 균열진전해석을 수행하여 균열을 모사할 수 있을 것으로 기대된다.
        4,000원
        14.
        2018.05 구독 인증기관·개인회원 무료
        In this study, the effect of dry shrinkage of concrete pavement due to seasonal changes was analyzed by comparing the results of finite element analysis with the temperature and strain measurements at Incheon airport pavement. To measure the behavior of slab by environmental condition in site, static strain gauges and thermometers were installed. To predict changes in the properties of concrete slab, experiments were conducted in site as well as in the lab. The considered parameters of FEA were pavement conditions according to seasonal and material properties change. The results of field measurements and the strain by FEA analysis were different in terms of the effects of drying shrinkage. This is due to humidity changes not applied to input values during FEA analysis. In this study, the difference between the results of field measurements and the results of the finite element model analysis was used to identify the drying shrinkage occurring on the concrete slab. Long-term data analysis in the future will enable the analysis of the trends in drying shrinkage in airport concrete pavement. This study was supported by Incheon International Airport Corporation(BEX00625).
        15.
        2017.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 논문에서는 2개 이상의 기하형상이 순응 또는 비순응 경계면에서 접합된 멀티패치 문제에 대한 아이소-지오메트릭 해석에 대해서 연구하였다. 패치 경계면에서 응력의 연속성을 표현하는 방법으로 Nitsche 방법론과 마스터-슬레이브 방법에 기반한 방법론에 대해서 지배방정식을 유도하고 아이소-지오메트릭 이산화를 수행하였다. 멀티패치 문제에 대해서 두 방법 론의 차이점을 간단하게 비교하였으며, 후처리 과정에서 사용되는 NURBS 곡면 기반의 응력 복원법에 대해서 기술하였다. 수치예제에서 비순응 경계면을 가지는 멀티패치 빔 문제를 통해 Nitshce 방법론을 검증하였으며, 응력집중을 가지는 문제에서 소개된 두 방법론이 유사한 결과를 보이는 것을 확인하였다. 소개된 NURBS 곡면 기반의 응력 복원법을 후처리에서 도입할 경우 멀티패치 문제의 경계면에서 개선된 연속적인 응력을 보임을 알 수 있다.
        4,000원
        16.
        2017.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        PURPOSES: In this study, a three-dimensional nonlinear finite element analysis (FEA) model for airport concrete pavement was developed using the commercial program ABAQUS. Users can select an analysis method and set the range of input parameters to reflect actual conditions such as environmental loading.METHODS : The geometrical shape of the FEA model was chosen by considering the concrete pavement located in the third-stage construction site of Incheon International Airport. Incompatible eight-node elements were used for the FEA model. Laboratory test results for the concrete specimens fabricated at the construction site were used as material properties of the concrete slab. The material properties of the cement-treated base suggested by the Federal Aviation Administration(FAA) manual were used as those of the lean concrete subbase. In addition, preceding studies and pavement evaluation reports of Incheon International Airport were referred for the material properties of asphalt base and subgrade. The kinetic friction coefficient between the concrete slab and asphalt base acquired from a preceding study was used for the friction coefficient between the layers. A nonlinear temperature gradient according to slab depth was used as an input parameter of environmental loading, and a quasistatic method was used to analyze traffic loading. The average load transfer efficiency obtained from an Heavy falling Weight Deflectomete(HWD) test was converted to a spring constant between adjacent slabs to be used as an input parameter. The reliability of the FEA model developed in this study was verified by comparing its analysis results to those of the FEAFAA model.RESULTS : A series of analyses were performed for environmental loading, traffic loading, and combined loading by using both the model developed in this study and the FEAFAA model under the same conditions. The stresses of the concrete slab obtained by both analysis models were almost the same. An HWD test was simulated and analyzed using the FEA model developed in this study. As a result, the actual deflections at the center, mid-edge, and corner of the slab caused by the HWD loading were similar to those obtained by the analysis.CONCLUSIONS : The FEA model developed in this study was judged to be utilized sufficiently in the prediction of behavior of airport concrete pavement.
        4,000원
        17.
        2017.06 구독 인증기관 무료, 개인회원 유료
        The paper applies CFD numerical simulation technology, selects the typical urban commercial block as the research object, uses PM I 0 which are from automobile exhausted gas as the source of pollution, simulates the spatial density di stribution of the inhalable pa11icle, verifies the accuracy based on the monitoring data and reveals the diffusion rule of atmospheric pollutants in the three dimensional block space. The results show that there is a close relationship between the diffusion effect of the contaminated gas and three dimensional landscape pattern in blocks. At different height levels such as I 0 meters, 30 meters and 50 meters, the decreasing trend of the density of the pollutants and the uniformity of the spatial distribution are quite obvious. The height of the buildings along the streets, the space combination and the shape of the buildings themselves determine the inner smoothness of the streets. In the urban planning, one must fully consider the effect of three dimensional pattern on air pollution in blocks. From the aspects of urban ventilation, open space, height of the horizon line and disheartened space of the bottom, three dimensional landscape pattern of urban blocks should be optimized, which can effectively improve the current situation of severe atmospheric pollution.
        4,000원
        18.
        2017.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In recent years, the number of earthquakes has increased worldwide. There has been an extreme increase on the Korea Peninsula, which is considered a safety zone for earthquakes. In particular, in the event of earthquakes, most structures on the Korea Peninsula are severely damaged, because most are not designed to withstand them. Damage to and destruction of civil structures, such as bridges, nuclear facilities, and dams, is worse than that of other structures. It is necessary to evaluate and predict the extent of damage by earthquake magnitude, as the magnitude of earthquakes is increasing as well as the frequency. A major feature of the occurrence of earthquakes is uncertainty. For this reason, it is necessary to adopt a stochastic approach, and studies using this approach are increasing. However, although there have been several studies on bridges and nuclear facilities, there have been few studies on probabilistic seismic risk evaluation for multi-functional weirs. Thus, this study presents 3D multi-functional weirs and performs a time history analysis by using LS-DYNA, a general structure analysis program. Probabilistic seismic fragility assessment is conducted by Monte Carlo simulation.
        4,000원
        19.
        2016.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Incremental sheet forming (ISF) is a highly versatile and flexible process for rapid manufacturing of complex sheet metal parts. Compared to conventional sheet forming processes, ISF is of a clear advantage in manufacturing small batch or customized parts. ISF needs die-less machine alone, while conventional sheet forming requires highly expensive facilities like dies, molds, and presses. This equipment takes long time to get preparation for manufacturing. However, ISF does not need the full facilities nor much cost and time. Because of the facts, ISF is continuously being used for small batch or prototyping manufacturing in current industries.However, spring-back induced in the process of incremental forming becomes a critical drawback on precision manufacturing. Since sheet metal, being a raw material for ISF, has property to resilience, spring-back would come in the case.It is the research objective to investigate how geometrical shaping parameters make effect on shape dimensional errors. In order to analyze the spring-back occurred in the process, this study experimented on Al 1015 material in the ISF. The statistical tool employed experimental design with factors. The table of orthogonal arrays of L8 (27) are used to design the experiments and ANOVA method are employed to statistically analyze the collected data. The results of the analysis from this study shows that the type of shape and the slope of bottom are the significant, whereas the shape size, the shape height, and the side angle are not significant factors on dimensional errors. More error incurred on the pyramid than on the circular type in the experiments. The sloped bottom showed higher errors than the flat one.
        4,000원
        20.
        2016.10 구독 인증기관 무료, 개인회원 유료
        오늘날 현대사회의 양극화 현상은 단지 이념과 국가 그리고 자본주의 종말을 예고하고 있는 가진 자와 못 가진자의 분배문제에 그치지 않고 있다. 인류의 대 명제인 이성을 가진 동물이라는 인간 본성에도 양극화 현상이 일어나고 있어서, 마치 인간에서 이성이 분리되어 동물적 본능만이 작용하고 있는 것과 같은 현상들이 발생하고 있기 때문이다. 이는 현대사 회의 무한경쟁과 물질만능의 가치관 등 다양한 원인들이 내재되어 있지만, 탈종교시대의 특징으로서 윤회나 인과응보에 관한 믿음이 없고, 그저 현실세계에서 이기적인 삶을 살다 죽으면 그만이라는 가치기준이 형성되어 있는 것이 가장 큰 문제 로 지적되고 있다. 또한 이러한 상황은 오늘날 현대사회를 살아가는 인류의 몸과 마음 영혼까지 총체적으로 오염된 결과로 서 나타나고 있으며, 아울러 영혼과 사후세계, 인간세계에 대한 영계작용의 실제에 대한 연구가 부진하여 객관적인 근거가 부족하기 때문으로 파악되고 있다. 이에 따라 본 논문에서는 에너지 불멸의 법칙이라는 현대물리학의 이론에 기초하여 국내외에서 발생한 3건의 임사체험 사례에 대한 과학적 분석 결과를 근거로 하여, 영혼과 영혼 세계의 실재에 대한 객관화 연구를 시도하고 있다.
        4,000원
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