• Journal of the Korean Geophysical Society
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• v.5 no.2
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• pp.87-97
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• 2002

P wave travel-time delays have been analyzed and average travel-time anomalies due to lateral variation of the crustal structure have been calculated at the broad-band earthquake observatories of Korea Meteorology Administration (KMA) using the teleseismic deata collected during the period from 2000 to 2001. Maximum variation in the relative travel-time residuals is almost 1.5 seconds Azimuthal variation in the travel-time residuals is observed to indicate the existence of lateral P velocity heterogeneity beneath the stations with velocity contrasts of -4~4%. The estimated average travel-time delays are ranging from 0.05 to 0.3 seconds at the stations including Seoul, Chuncheon, Kanneung, Uljin, and Ulleung Island showing slow velocity contrasts of 0~4% P through the crust. Faster velocity contrasts of 0~4% have been observed at the stations including Seosan, Taejeon, Daegu, Seoguipo, and Busan showing average travel-time delays ranging from -0.05 to -0.3 seconds.

• Journal of the Korean Society for Nondestructive Testing
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• v.24 no.1
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• pp.38-44
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• 2004

An experimental study for a crane hook was performed to investigate the stress distribution along a certain line where the maximum and minimum stresses to be developed. On this line, the isoclinic fringe and/or principal stress direction is constant. The crane hook was modeled into a 2-dimensional plate made of urethane rubber called 'Photoflex' The Photoflex is very sensitive to a load and has low photoelastic fringe constant. The Tardy compensation method with the fringe sharpening process and the 4-step phase shifting method, was used for the photoelastic technique. Experimental results by photoelasticity were compared with the calculated stresses from the simple curved beam theory and tile finite element analysis. Ail the results were close to each other.

• The Journal of Korean Academy of Prosthodontics
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• v.46 no.5
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• pp.479-489
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• 2008

Statement of the problem: Under anatomical limitations on maxillary posterior region, a poor crown-to root ratio acting on dental implants can result in undesirable stress in surrounding bone, which in turn can cause bone defects and eventual failure of implants. Purpose: The purpose is to compare stress distribution due to different crown-root ratio and effect of splinting between natural teeth and implants in maxillary molar area under different loads. Material and methods: Analysis of stress arising supporting bone of the natural teeth and the implant was made with 3-dimensional finite element method. The model simulated naturel teeth was made with 2nd premolar and 1st molar in the maxillary molar region (Model T). The model simulated implants placed on same positions with two parallel implants of Straumann Dental Implant cemented abutment (Model I). Each model was designed in different crown-root ratio (0.7:1, 1:1, 1.25:1) and set cement type gold crown to make it non-splinted or splinted. After that, 300 N force was loaded to each model in five ways (Load 1: middle of occlusal table, Load 2: middle of buccal cusp, Load 3: middle of lingual cusp, Load 4: horizontal load to buccal cusp of anterior abutment only, Load 5: horizontal load to middle of buccal cusp of each abutment), and stress distribution was analyzed. Results and conclusion: On all occasions, stress was concentrated at the cervical region of the implant. Under load 1, 2 and 3, stress was not increased even when crown-root ratio increases, but under load 4 and 5, when crown-root ratio increases, stress also increased. There was difference in stress values between natural teeth and implants when crown-root ratio gradually increases; In case of natural teeth, splinting decreased stress under vertical and horizontal loads. In case of implants, splinting decreased stress under vertical loads 1,2 and 3, but increased maximal stress under loads 2 and 3. Under horizontal loads, splinting decreased stress, however the effect of splinting decreased under load 5 than load 4. Furthermore, the stress was increased, when crown-root ratio is 1.25:1. Clinical implications: This limited finite element study suggests that the stress on supporting bone may be increased under non-axial loads and poor crown-root ratio. Under poor crown-root ratio, excessive stress was generated at the cervical region of the implant, and decreased splinting effect for stress distribution, which can be related to clinical failure.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.4
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• pp.35-42
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• 2013

In this paper, the analog performance of FinFET structure was estimated by extracting the DC/AC characteristics of the 22 nm process FinFET structures with different layout considering spacer and SEG using 3D device simulator, Sentaurus. Based on the analysis results, layout methods to enhance the analog performance of multi-fin FinFET structures are proposed. By adding the spacer and SEG structures, the drive current of 1-fin FinFET increases. However, the unity gain frequency, $f_T$, reduces by 19.4 % due to the increase in the total capacitance caused by the added spacer. If the process element is not included in multi-fin FinFET, replacing 1-finger with 2-finger structure brings approximately 10 % of analog performance improvement. Considering the process factors, we propose methods to maximize the analog performance by optimizing the interconnect and gate structures.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.5B
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• pp.447-457
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• 2006

This paper presents a numerical model for the simulations of 2D depth-averaged flows. The shallow water equations are solved numerically by the Characteristic Dissipative Galerkin (CDG) finite element method. For validation, the developed model is applied to the hydraulic jump. The computed results are compared with the analytical solution, revealing good agreement. In addition, flow in a contracting channel showing standing waves is simulated. The calculated water surface profile appears to be qualitatively consistent with the observed data. The foregoing results indicate that the model is capable of simulating the abrupt change in flow field. Next, the model is applied to the flow in a $180^{\circ}$ curved channel. The simulated results show that the velocity near the inner bank is faster than that near the outer bank and the water depth near the inner bank is shallower than that near the outer bank. However, the simulated results show that the velocity distribution across the channel is almost uniform in the bend except the reach close to the end of the bend. This is due to the limitation of the governing equations in which the transverse convection of momentum by the secondary flows along a channel bend is not taken into account.

• 프린팅코리아
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• v.8 no.8
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• pp.42-49
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• 2009

인쇄물을 가장 많이 발주하는 산업부문은 출판업계라고 한다. 그 뒤를 따르고 있는 부문으로는 정부부문과 민간 및 공기업을 들 수 있다. 이 가운데 출판업계 및 정부부문의 인쇄물 발주가 비교적으로 명확한데 비해서 기업부문에서의 발주는 정확한 자료 및 통계를 찾기가 쉽지 않은 상황이다. 이는 기업에서 발주하는 인쇄물의 종류가 다양하고 부서에 따라 예산이 별도로 편성되는 경우가 많다는데서 그 이유를 찾을 수 있다. 뿐만 아니라 항목별로 다르게 편성되기 때문에 똑같은 인쇄물이고 해도 마케팅 부문으로 잡히지 않는 경우도 적지 않다. 이런 저런 어려운 요소들을 감안하고 나서 인쇄물에 관련된 예산을 추정해 본다고 해도 정확한 수치를 잡아내기란 여전히 어려운 일이 되고 있다. 각 기업들이 마케팅과 관련된 예산이다 보니 정확한 수치를 공개하는 것을 꺼리는 경우가 많고 하나의 항목으로 회계 처리되는 것이 아니기 때문이다. 그렇지만 경제의 성장과 함께 광고산업의 규모가 커지고 있으며 이에 따른 기업들의 마케팅도 활발하게 전개되면서 마케팅 도구의 하나인 인쇄홍보물의 사용도 함께 증가하는 경향을 보이고 있다. 비록 마케팅과정에서 사용되는 마케팅 도구로서의 인쇄홍보물의 파악이 어렵고, 1회적인 경우가 많기는 하지만 점차적으로 정기적인 마케팅의 하나라는 인식이 확산되면서 한 번의 인쇄물 수주가 꾸준한 거래관계로 발전하는 사례가 점자 증가하고 있다. 또한 광고 및 마케팅 부문을 대행사에 위탁하는 대기업의 물량을 수주하는 경우가 생긴다면 예상외로 우량한 거래처를 확보할 수 있다는 점이 업계의 관심을 끌기에 충분한 매력이 되고 있다. 아직까지 물량면이나 인지도면에서 상대적으로 낮게 평가되고 있지만 앞으로의 성장이 예견되고 있는 민간과 공기업 부문의 마케팅에서 인쇄홍보물이 갖고 있는 위상과 고객사들의 인식에 대해 알아본다.

• Journal of Korean Society of Steel Construction
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• v.14 no.1
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• pp.69-78
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• 2002

This paper describes the analysis results for tensile behavior of tubular column to H-beam connection with T stiffeners. Using the elasto-plastic finite element method, analysis results are compare with experimental results. Parametric analyses with different size of T-stiffener have conducted to understand the stress distribution at the connections. Stress concentration in elastic region and PEEQ distribution in plastic region are plotted for different shape. The results of analysis were applied to design equations and were checked for the applicability of design equations.

• The Transactions of the Korea Information Processing Society
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• v.4 no.8
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• pp.1930-1939
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• 1997

In this paper, we analyze the fault diameter and fault tolerance of Gray cube proposed recently in [12]. fault diameter of an interconnection network is one of the important network measures concerning the distance between nodes when some nodes fail. It is showed that fault diameter of n-dimensional Gray cube having $2^n$ nodes is [(n+1)/2]+2, ($n{\ge}3$). It means the increment of the longest distance between nodes under node-failure is only constant factor. Comparing the result with the fault diameter of well-known hypercube, the longest routing distance of a message in a Gray cube under node-failure is about the half of that hypercube.

• International Journal of Highway Engineering
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• v.11 no.1
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• pp.165-175
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• 2009

With the current move towards adopting mechanistic-empirical concepts in the design of pavement structures, state-of-the-art mechanistic analysis methodologies are needed to determine accurate pavement responses, such as stress, strain, and deformation. Previous laboratory studies of pavement foundation geomaterials, i.e., unbound granular materials used in base/subbase layers and fine-grained soils of a prepared subgrade, have shown that the resilient responses followed by nonlinear, stress-dependent behavior under repeated wheel loading. This nonlinear behavior is commonly characterized by stress-dependent resilient modulus material models that need to be incorporated into finite element (FE) based mechanistic pavement analysis methods to predict more realistically predict pavement responses for a mechanistic pavement analysis. Developed user material subroutine using aforementioned resilient model with nonlinear solution technique and convergence scheme with proven performance were successfully employed in general-purpose FE program, ABAQUS. This numerical analysis was investigated in predicted critical responses and domain selection with specific mesh generation was implemented to evaluate better prediction of pavement responses. Results obtained from both axisymmetric and three-dimensional (3D) nonlinear FE analyses were compared and remarkable findings were described for nonlinear FE analysis. The UMAT subroutine performance was also validated with the instrumented full scale pavement test section study results from the Federal Aviation Administration's National Airport Pavement Test Facility (FAA's NAPTF).

• Journal of Korean Society of Steel Construction
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• v.23 no.4
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• pp.429-438
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• 2011

In this study, the explicit numerical algorithm was proposed to simulate the stress erection process and ultimate-load analysis of the strarch (stressed arch) system. The strarch system is a unique and innovative structural system and member prestress comprising prefabricated plane truss frames erected through a post-tensioning stress erection procedure. The flexible bottom chord, which has sleeve and gap details, is closed by the reaction force of the prestressing tendon. The prestress imposed on the tendon will enable the strarch system to be erected. This post-tensioning process is called "stress erection process." During this process, plastic rigid-body rotation occurs to the flexible top chord due to the excessive amount of plastic strain, and the structural characteristic is unstable. In this study, the dynamic relaxation method (DRM) was adopted to calculate the nonlinear equilibrium equation of the system, and a displacement-based finite-element-formulated filament beam element was used to simulate the nonlinear behavior of the top chord sections of the strarch system. The section of the filament beam element was composed by the amount of filaments, which can be modeled by various material models. The Ramberg-Osgood and bilinear kinematic elastic plastic material models were formulated for the nonlinear material behaviors of the filaments. The numerical results that were obtained in the present study were compared with the experiment results of the stress erection and with the results of the ultimate-load analysis of the strarch unit frame. The results of the present studies are in good agreement with the previous experiment results, and the explicit DRM enabled the analysis of the post-buckling behaviors of the strarch unit frame.