• East Asian Economic Review
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• 제27권4호
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• pp.303-325
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• 2023

This paper examines how APEC has transformed itself into an international forum for the vision of regional integration. It aims to quantify the documentation produced by the international organization and provide quantifiable evidence that aligns with prior knowledge rather than relying solely on intuition. For this purpose, I use various text mining techniques to extract multi-dimensional features from the text of APEC Leaders' Declarations from 1993 to 2023. In terms of interest and expectations for APEC as a forum, it is found that members have experienced two major peaks and troughs over the last three decades. It is found that the change point coincides with the Asian financial crisis of 1997 and the tensions between the United States and China since 2017. To explore more various aspects of economic integration in the Asia-Pacific region, this study also considers how consistently APEC has been an international forum for addressing issues, which members are active, and how members have clustered based on their views of APEC.

• 한국디지털건축인테리어학회논문집
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• 제12권4호
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• pp.97-105
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• 2012

This study aims to evaluate Rietveld's creative design style and concepts. To this end, I looked into the evaluation of major researchers on Rietveld, classified all his works into four groups according to the design types and analyzed them. As follows: based on the results of the analysis of works I concluded. First, Rietveld created the concept of the spatial extension to the ingenious joint which had the structural node formed of three listels with quadrangular section. It is the design innovation that led to liberate the closed construction. Second, Rietveld had opened up the possibility to neutralize the gravitational three-dimensional works. He subtracted the weight in the direction of gravity from the three-dimensional structure of the works and painted the three primary colors on them partially to get rid of the original material color. Therefore they looked like the forms liberated from gravity. Third, Rietveld ripped off the surfaces of cube through several formative experiments and decomposed the volume into the tesseract. Through this method of realizing the new plastic concepts, he completed the architectural models of weightlessness. Fourth, Rietveld opened the possibility of the realization of the three-dimensional works integrated all space and time in the one-pieced works and the folded works. Fifth, Rietveld steadily experimented and realized the internal and external integration of time and space in his later works.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 추계학술대회논문집B
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• pp.570-577
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• 2001

Three-dimensional time-dependent flow past a circular cylinder is numerically investigated using direct numerical simulation for Reynolds number 280 and 300. The higher-order finite difference scheme is employed for the spatial distributions along with the second order Adams-Bashforth and the first order backward-Euler time integration. In x-y plane, the convection term is applied by the 5th order upwind scheme and the pressure and viscosity terms are applied by the 4th order central difference. And in spanwise, Navier-Stokes equation is distributed using of Spectral Method. At Reynolds number 259 the two-dimensional wake becomes linearly unstable to a second branch of modes with wavelength about 1.0 diameters at onset (B-mode). Present results of three-dimensional effects of in wake of a circular cylinder is represented with spanwise and streamwise vorticity contours as Reynolds numbers.

• 한국해안해양공학회지
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• 제10권1호
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• pp.27-36
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• 1998

물의 유동을 해석하기 위한 3차원 수치모형이 개발되었다 모형은 균질류에 대한 $\sigma$-좌표에서 방정식들 을 유한요소법을 사용하여 해석한다. 모형의 정확성을 정토하기 위하여 1차원 수로에서 취송류 분포, 정사각형 호수에서 취송류 분포를 해석하고 해석해와 비교 검증하였으며, 마산-진해만에서 조류분포를 계산하고 현장 관측자료와 비교 검증하였다. 계산결과가 비교된 해석해 및 관측치와 대체로 일치하는 양호한 결과를 보였다. 따라서, 개발된 모형은 복잡한 육지경계를 갖는 자연 수괴의 3차원적 순환현상을 해석하는 데 널리 활용될 수 있을 것이다

• 한국산업융합학회 논문집
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• 제20권2호
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• pp.195-204
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• 2017

Predicting the failure life of automated manufacturing systems can reduce overall downtime, maintenance costs, and total plant operation costs. Therefore, there is a growing interest in fatigue failure mechanisms as the safety or service life assessment of manufacturing systems becomes an important issue. In particular, fretting fatigue is caused by repeated tangential stresses that are generated by friction during small amplitude oscillatory movements or sliding between two surfaces pressed together in intimate contact. Previous studies in fretting fatigue have observed size effects related to contact width such that a critical contact width exists where there is drastic change in the fretting fatigue life. However, most of them are the two-dimensional finite element analyses based on the plane strain assumption. The purpose of this study is to investigate the contact size effects on the three-dimensional finite element model of a finite width of a flat specimen and a cylindrical pad exposed to fretting fatigue. The contact size effects were analyzed by means of the stress and strain averages at the element integration points of three-dimensional finite element model. This study shows that the fretting fatigue life of manufacturing systems can be predicted by three-dimensional finite element analysis based on SWT critical plane model.

• International Journal of CAD/CAM
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• 제6권1호
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• pp.3-8
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• 2006

The application of three-dimensional (3-D) CAD has been popularized for design and production and digital manufacturing has been spreading in many industrial fields. By simulation of the production process using 3-D digital models, which are the core of CIM (Computer Integrated Manufacturing) system, the efficiency and safety of production are improved at each stage of work, and optimization of manufacturing can be achieved. This paper firstly describes the concept of "simulation based production" in shipbuilding and also digital manufacturing; the 3-D CAD system is indispensable for effective simulation because ship structure is three dimensionally complex. By simulation, "computer optimized manufacturing" can be possible. The most effective fields of simulation in shipbuilding are in jobs where many parties have to cooperate, while existing two-dimensional drawings are hardly observed the whole structures due to interference between structures or equipment of complex shape. In this paper some examples of the successful application in IHIMU (IHI Marine United Inc.) are shown: assembly of a pipe unit, erection of a complex hull block, carriage of equipment, installation of a propeller, and access in an engine room.

• Journal of Yeungnam Medical Science
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• 제26권1호
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• pp.15-23
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• 2009

Constant technological developments in coronary artery disease have contributed to the assessment of both the presence of coronary stenosis and its hemodynamic consequences. Hence, noninvasive imaging helps guide therapeutic decisions by providing complementary information on coronary morphology and on myocardial perfusion and metabolism. This can he done using single photon emission computed tomography (SPECT) or positron emission tomography (PET) and multidetector CT (MDCT). Advances in image-processing software and the advent of SPECT/CT and PET/CT have paved the way for the combination of image datasets from different modalities, giving rise to hybrid imaging. Three dimensional cardiac hybrid imaging helped to confirm hemodynamic significance in many lesions, add new lesions such as left main coronay artery disease, exclude equivocal defects, correct the corresponding arteries to their allocated defects and identify culprit segment. Cardiac hybrid imaging avoids the mental integration of functional and morphologic images and facilitates a comprehensive interpretation of coronaty lesions and their pathophysiologic adequacy by three dimensional display of fused images, and allows the best evaluation of myocardial territories and the coronary-artery branches that serve each territory. This integration of functional and morphological information were feasible to intuitively convincing and might facilitate development of a comprehensive non-invasive assessment of coronary artery disease.

• 전자통신동향분석
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• 제36권3호
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• pp.12-22
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• 2021

Since the technical realization of self-aligned planar complementary metal-oxide-semiconductor field-effect transistors in 1960s, semiconductor manufacturing has aggressively pursued scaling that fruitfully resulted in tremendous advancement in device performances and realization of features sizes smaller than 10 nm. Due to many intrinsic material and technical obstacles, continuing the scaling progress of semiconductor devices has become increasingly arduous. As an effort to circumvent the areal limit, stacking devices in a three-dimensional fashion has been suggested. This approach is commonly called monolithic three-dimensional (M3D) integration. In this work, we examined technical issues that need to be addressed and overcome to fully realize energy efficiency, short latency and cost competency. Full-fledged M3D technologies are expected to contribute to various new fields of artificial intelligence, autonomous gadgets and unknowns, which are to be discovered.

• Geomechanics and Engineering
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• 제34권1호
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• pp.29-41
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• 2023

The 3D geospatial modeling of geotechnical information can aid in understanding the geotechnical characteristic values of the continuous subsurface at construction sites. In this study, a geostatistical optimization model for the three-dimensional (3D) mapping of subsurface stratification and the SPT-N value based on a trial-and-error rule was developed and applied to a dam emergency spillway site in South Korea. Geospatial database development for a geotechnical investigation, reconstitution of the target grid volume, and detection of outliers in the borehole dataset were implemented prior to the 3D modeling. For the site-specific subsurface stratification of the engineering geo-layer, we developed an integration method for the borehole and geophysical survey datasets based on the geostatistical optimization procedure of ordinary kriging and sequential Gaussian simulation (SGS) by comparing their cross-validation-based prediction residuals. We also developed an optimization technique based on SGS for estimating the 3D geometry of the SPT-N value. This method involves quantitatively testing the reliability of SGS and selecting the realizations with a high estimation accuracy. Boring tests were performed for validation, and the proposed method yielded more accurate prediction results and reproduced the spatial distribution of geotechnical information more effectively than the conventional geostatistical approach.

• 한국전산유체공학회지
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• 제2권1호
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• pp.8-12
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• 1997

The three-dimensional Euler equations are solved numerically for the analysis of contraction flows in wind or water tunnels. A second-order finite difference method is used for the spatial discretization on the nonstaggered grid system and the 4-stage Runge-Kutta scheme for the numerical integration in time. In order to speed up the convergence, the local time stepping and the implicit residual-averaging schemes are introduced. The pressure field is obtained by solving the pressure-Poisson equation with the Neumann boundary condition. For the evaluation of the present Euler solver, numerical computations are carried out for three contraction geometries, one of which was adopted in the Large Cavitation Channel for the U.S. Navy. The comparison of the computational results with the available experimental data shows good agreement.