• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.11 no.5
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• pp.89-100
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• 2001

The Ritz method Is applied In a three-dimensional (3-D) analysis to obtain accurate frequencies for thick. linearly tapered. annular plates. The method is formulated for annular plates haying any combination of free or fixed boundaries at both Inner and outer edges. Admissible functions for the three displacement components are chosen as trigonometric functions in the circumferential co-ordinate. and a1gebraic polynomials in the radial and thickness co-ordinates. Upper bound convergence of the non-dimensional frequencies to the exact values within at least four significant figures is demonstrated. Comparisons of results for annular plates with linearly varying thickness are made with ones obtained by others using 2-D classical thin place theory. Extensive and accurate ( four significant figures ) frequencies are presented 7or completely free. thick, linearly tapered annular plates haying ratios of average place thickness to difference between outer radius (a) and inner radius (b) radios (h$_{m}$/L) of 0.1 and 0.2 for b/L=0.2 and 0.5. All 3-D modes are included in the analyses : e.g., flexural, thickness-shear. In-plane stretching, and torsional. Because frequency data liven is exact 7o a\ulcorner least four digits. It is benchmark data against which the results from other methods (e.g.. 2-D 7hick plate theory, finite element methods. finite difference methods) and may be compared. Throughout this work, Poisson\`s ratio $\upsilon$ is fixed at 0.3 for numerical calculations.s.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.2D
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• pp.277-285
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• 2008

X-ray images are wildly used in medical applications, and these can be more efficiently find scoliosis which is appearing during the growth of human skeleton than others. This research is focused on the calibration of X-ray image and three-dimensional coordinate determination of objects. Three-dimensional coordinate of objects taken by X-ray are determined by two step procedure. Firstly, interior and exterior orientation parameters are determined by camera calibration using Primary Calibration Object (PCO) which has two sides with embedded radiopaque steel ball. Secondly, calibration cage coordinates which is composed of two acrylic sheets that are perpendicular to X-ray source are determined by the parameters. Three-dimensional coordinates of calibration cage determined by photogrammetric technique are compared with that of Coordinate Measuring Machine (CMM). Though the accuracy analysis, X direction which is parallel to X-ray source error values are relatively higher than those of Y and Z directions. But, the accuracies of Y and Z axis are approximately -3 mm to 3 mm. From the research results, it is considered that photogrammetric technique is applied to determine three-dimensional coordinates of patients or assist to make medical devices.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2007.06a
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• pp.121-124
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• 2007

This paper describes the development of a brickwork game with three-dimensional computer graphics as one of web-based game contents. Client user using web can access and run lava applet program with the independence of hardware system. It consists of graphic user interface module, initial space generation module, event handler module, player control module, and thread control module. It uses 3-D array data structure for the 3-D graphic objects that are located in three-dimensional space for high-speed object searching and sorting. It enhances to compare with predetermined construction in three-dimensional space. We can use the developed racing game to inform game users of information for an advertisement like tourism information, and can apply the proposed 3-D drawing technology to 3-D game graphic engine core.

• Archives of Plastic Surgery
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• v.50 no.3
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• pp.254-263
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• 2023

Background The three-dimensional (3D) evaluation of skeletal stability after orthognathic surgery is a time-consuming and complex procedure. The complexity increases further when evaluating the surgery-first orthognathic approach (SFOA). Herein, we propose and validate a simple time-saving method of 3D analysis using a single software, demonstrating high accuracy and repeatability. Methods This retrospective cohort study included 12 patients with skeletal class 3 malocclusion who underwent bimaxillary surgery without any presurgical orthodontics. Computed tomography (CT)/cone-beam CT images of each patient were obtained at three different time points (preoperation [T0], immediately postoperation [T1], and 1 year after surgery [T2]) and reconstructed into 3D images. After automatic surface-based alignment of the three models based on the anterior cranial base, five easily located anatomical landmarks were defined to each model. A set of angular and linear measurements were automatically calculated and used to define the amount of movement (T1-T0) and the amount of relapse (T2-T1). To evaluate the reproducibility, two independent observers processed all the cases, One of them repeated the steps after 2 weeks to assess intraobserver variability. Intraclass correlation coefficients (ICCs) were calculated at a 95% confidence interval. Time required for evaluating each case was recorded. Results Both the intra- and interobserver variability showed high ICC values (more than 0.95) with low measurement variations (mean linear variations: 0.18 mm; mean angular variations: 0.25 degree). Time needed for the evaluation process ranged from 3 to 5 minutes. Conclusion This approach is time-saving, semiautomatic, and easy to learn and can be used to effectively evaluate stability after SFOA.

• JSTS:Journal of Semiconductor Technology and Science
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• v.4 no.3
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• pp.196-203
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• 2004

A three-dimensional (3D) IC technology platform is presented for high-performance, low-cost heterogeneous integration of silicon ICs. The platform uses dielectric adhesive bonding of fully-processed wafer-to-wafer aligned ICs, followed by a three-step thinning process and copper damascene patterning to form inter-wafer interconnects. Daisy-chain inter-wafer via test structures and compatibility of the process steps with 130 nm CMOS sal devices and circuits indicate the viability of the process flow. Such 3D integration with through-die vias enables high functionality in intelligent wireless terminals, as vertical integration of processor, large memory, image sensors and RF/microwave transceivers can be achieved with silicon-based ICs (Si CMOS and/or SiGe BiCMOS). Two examples of such capability are highlighted: memory-intensive Si CMOS digital processors with large L2 caches and SiGe BiCMOS pipelined A/D converters. A comparison of wafer-level 3D integration 'lith system-on-a-chip (SoC) and system-in-a-package (SiP) implementations is presented.

• Proceedings of the KIEE Conference
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• 1989.07a
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• pp.477-480
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• 1989

In this paper, we introduce the three-dimensional Korean character display by using 2D fonts and character depth. Character segments are designed by the set of vertex at run time. Character depth is applied for 3D visualization. And, the variation of eye-point and distance of object is used for 3D character animation.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.32A no.8
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• pp.94-106
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• 1995

A three-dimensional(3D) Monte Carlo simulator for boron ion implantation into <100>single-crystal silicon considering the mask structure has been developed to predict the mask-dependent impurity doping profiles of the implanted boron at low energies into the reduced area according to the trend of a reduction in the size of semiconductor devices. All relevant important parameters during ion implantation have been taken into account in this simulator. These are incident energy, tilt and rotation of wafer, orientation of silicon wafer, presence of native silicon dioxide layer, dose, wafer temperature, ion beam divergence, masking thickness, and size and structure of open window in the mask. The one-dimensional(1D) results obtained by using the 3D simulator have been compared with the SIMS experiments to demonstrate its capabilities and confirem its reliability, and we obtained relatively accurate 1D doping profiles. Through these 3D simulations considering the hole structure and its size, we found the mask effects during boron ion implantation process.

• Journal of the korean academy of Pediatric Dentistry
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• v.47 no.1
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• pp.17-24
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• 2020

The purpose of this study was to evaluate the accuracy and precision of the three-dimensional (3D) imaging system of children's facial soft tissue by comparing linear measurements. The subjects of the study were 15 children between the ages of 7 and 12. Twenty-three landmarks were pointed on the face of each subject and 16 linear measurements were directly obtained 2 times using an electronic caliper. Two sets of 3D facial images were made by the 3D scanner. The same 16 measurements were obtained on each 3D image. In the accuracy test, the total average difference was 0.9 mm. The precision of 3D photogrammetry was almost equivalent to that of direct measurement. Thus, 3D photogrammetry by the 3D scanner in children had sufficient accuracy and precision to be used in clinical setting. However, the 3D imaging system requires the subject's compliance for exact images. If the clinicians provide specific instructions to children while obtaining 3D images, the 3D device is useful for investigating children's facial growth and development. Also the device can be a valuable tool for evaluating the results of orthodontic and orthopedic treatments.

• Journal of Korea Multimedia Society
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• v.13 no.11
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• pp.1657-1666
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• 2010

Underwater wireless sensor networks (UWSN) need stable efficient data transmission methods because of environmental characteristics such as limited energy resource, limited communication bandwidth, variable propagation delay and so on. In this paper, we explain an enhanced hybrid transmission method that uses a hexagon tessellation with an ideal cell size in a two-dimensional underwater wireless sensor network model (2D) that consists of fixed position sensors on the bottom of the ocean. We also propose an energy efficient sensing and communication coverage method for effective data transmission in a three-dimensional underwater wireless sensor network model (3D) that equips anchored sensors on the bottom of the ocean. Our simulation results show that proposed methods are more energy efficient than the existing methods for each model.

• Smart Structures and Systems
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• v.13 no.4
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• pp.659-683
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• 2014

The static analysis of structures with arbitrary cross-section geometry and material lamination via a refined one-dimensional (1D) approach is presented in this paper. Higher-order 1D models with a variable order of expansion for the displacement field are developed on the basis of Carrera Unified Formulation (CUF). Classical Euler-Bernoulli and Timoshenko beam theories are obtained as particular cases of the first-order model. Numerical results of displacement, strain and stress are provided by using the finite element method (FEM) along the longitudinal direction for different configurations in excellent agreement with three-dimensional (3D) finite element solutions. In particular, a layered thin-walled cylinder is considered as first assessment with a laminated conventional cross-section. An atherosclerotic plaque is introduced as a typical structure with arbitrary cross-section geometry and studied for both the homogeneous and nonhomogeneous material cases through the 1D variable kinematic models. The analyses highlight limitations of classical beam theories and the importance of higher-order terms in accurately detecting in-plane cross-section deformation without introducing additional numerical problems. Comparisons with 3D finite element solutions prove that 1D CUF provides remarkable three-dimensional accuracy in the analysis of even short and nonhomogeneous structures with arbitrary geometry through a significant reduction in computational cost.