• Journal of KSNVE
• /
• v.9 no.4
• /
• pp.703-713
• /
• 1999

A side mirror is an important safety tool with which the driver can observe objects out of sight. This paper presents an organized design technology for the side mirror of improved vibration characteristics. Resonance response to forced vibration is critical to observability through the mirror to be designed. This study aims at the reduction of vibration level by the modification of mirror structures and consequent effects are predicted by computer simulations. We used a three-dimensional solid modeling and the modal and frequency analysis ; Pro/Engineer is used as a solid modeler; Pro/Mechanica for vibration analysis. The simulation results are compared with those obtained in experiemnts to check the validity by the three-dimensional modeling. The design technique of side mirror has been established and found to be effective in vibration analysis of redesigned parts.

• Journal of the Korean Society for Precision Engineering
• /
• v.12 no.1
• /
• pp.5-14
• /
• 1995

An optical measurement method of three dimensional surface profiles which is named the slit beam projection is suggested and practically implemented. This method is intended especially for noncontact and fast digitization of sculptured surfaces for CAD modeling and die manufacturing. Its basic principles are based on geometric optics. Deatiled optical principles and an sub-pixel image processing technique to enhance the measuring resolutions are described in this study. The measuring performances of the slit beam projection are presented and discussed to demonstrate that an actual measuring accuracy of below .+-. 0.2mm can be achived over the whole measuring range(500mm*300mm*200mm)

• Transactions of the Korean Society of Mechanical Engineers
• /
• v.18 no.12
• /
• pp.3159-3174
• /
• 1994

A simple octree encoding algorithm based on a tetrahedron root has been developed to be used for fully automatic generation of three dimensional finite element meshes. This algorithm starts octree decomposition from a tetrahedron root node instead of a hexahedron root node so that the terminal mode has the same topology as the final tetrahedral mesh. As a result, the terminal octant can be used as a tetrahedral finite element without transforming its topology. In this part(I) of the thesis, an efficient algorithm for the tetrahedron-based octree is proposed. For this development, the following problems have been solved, : (1) an efficient data structure for storing the octree and finite elements, (2) an encoding scheme of a tetrahedral octree, (3) a neighbor finding technique for the tetrahedron-based octree.

• Proceedings of the Korean Association of Geographic Inforamtion Studies Conference
• /
• 2004.10a
• /
• pp.13-18
• /
• 2004

In this study, a new method is proposed generating 3D wire-frames of building using the lowest level topology, points, which are input by human operators. Through the procedure, it is possible to make prediction occlusion points and generate the topology automatically among points, lines, surfaces from buildings. In order to adjust the error of initial values which are input manually, the least squares adjustment for model-image fitting is carried out using the edge information of aerial imagery. And also, model fitting procedure is done making all surfaces plane of buildings by the least squares adjustment. As a result of those procedure, 3D building models are refined similar to real figures of buildings.

• Proceedings of the Korean Information Science Society Conference
• /
• 2012.06c
• /
• pp.408-409
• /
• 2012

본 논문에서 우리는 실시간 COI(Context-of-Interest) 등록에서의 증강현실 기반의 유기적 사용자 인터페이스를 제안한다. 먼저 동적으로 변하는 현실 공간의 사용자와 환경 정보를 반영한 증강형태(Augmented Form)의 변형을 가능하게하는 유기적 증강현실을 소개한다. 이를 사전에 정의된 증강현실 마커의 제약을 극복하는 실시간 삼차원 모델링 및 추적 기술에 적용하여 작업의 단계와 흐름에 따라 동적으로 변경되는 제공되는 증강 가이드를 구현하였다. 결과적으로 사용자는 응용 시스템에 대한 사전 학습이 부족하더라도 유기적인 가이드 정보에 따라 직관적인 작업 수행을 기대할 수 있다.

• The Journal of the Korea Contents Association
• /
• v.12 no.9
• /
• pp.136-145
• /
• 2012

This research proposes a pattern making method for women's bodice by the characters of body types and develops bodice dress forms on their body shapes applying 3D body scan data. 515 women's body scan data was collected and analyzed factor and cluster analysis. Three body types were characterized in normal, obese, and slim group. In each group, 10 subjects were selected. 20 parts in 3D anthropometric data were measured using Autocad program. The amount of waist dart was calculated and three types of basic bodice pattern were developed using the calculated darts data. The amount and the position of front dart and side dart were different at obese group in comparison of normal and thin group. The three types of basic bodice model were made by the basic bodice pattern, and each model was scanned by 3D scanner to make 3D bodice dress forms. Three types of bodice dress forms were rendered using 3D max program. Bodice dress forms had the dart lines and were useful to draft patterns to fit their body shape.

• Journal of the Korean Institute of Landscape Architecture
• /
• v.46 no.2
• /
• pp.1-13
• /
• 2018

This work discusses the major roles of digital technologies in the history of landscape architectural drawing, and offers a critique of the dominant trend towards realism in recent digital landscape representations. During the period of transition from conventional drawing tools, computer technologies generally functioned as mechanical tools to imitate prior manual techniques. Specifically, the GIS was served as a mechanical tool to efficiently process the manual layer cake; CAD software generally functioned to translate physical models to two-dimensional construction documents while graphic software generally functioned as a tool to perform processes similar to those of manual collage and montage techniques. Recent digital landscape drawings tend to adopt a realistic depiction like the painting of landscape appearance. In the representations, discernible traces of cutting and assembling are removed via graphic software; thus, the complete representations are perceived as if they were a copy of an actual landscape. The realistic images are an easy way to communicate with the public. However, it is difficult to achieve a full embodiment of all of the multisensory characteristics of a landscape through these visuals. They often deceive viewers by visualizing idealized conditions of not-yet-actualized landscapes and production of the final images takes up a large portion of the overall design process. Alternatively, 3D digital modeling of landscape performance and creative uses of digital technologies during the overall design process, as well as hybridized techniques with different drawing techniques and technologies, provide the opportunity to explore various aspects of a landscape.

• The Journal of Engineering Geology
• /
• v.16 no.4 s.50
• /
• pp.337-349
• /
• 2006

Seven hundred and fifty one fractures of the rhyolitic tuffaceous rock masses were mapped using 6 scanlines placed on rock slope exposures that were within 8.02 km of Busan-Ulsan highway. These data were analyzed to find the number of fracture sets that exist in the rock slopes and the probability distributions of orientation, spacing, trace length and fracture size in 3-D for each of the fracture sets. All the fracture set orientation distributions exhibit high variability. The Fisher distributions were found to be unsuitable to represent the statistical distribution of orientation for most of the fracture sets. The probability distributions, gamma, exponential and lognormal were found to be highly suitable to represent the distribution of spacing and semi-trace length of fracture sets. In obtain-ing these distributions, corrections were applied for sampling biases associated with spacing and trace length. The generated fracture system in 3-D was used to make predictions of fracture traces for each fracture set on 2-D win-dows. Developed stochastic 3-D fracture network for the rock mass was validated by comparing statistical proper-ties of the observed fracture traces on scanlines with the predicted fracture traces on the scanlines. This exercise fumed out to be successful.

• Journal of Soil and Groundwater Environment
• /
• v.13 no.4
• /
• pp.8-21
• /
• 2008

A series of three-dimensional numerical simulations using a hydrodynamic dispersion numerical model is performed to analyze quantitatively impacts of layered heterogeneity of geologic media and groundwater pumping schemes on groundwater flow and salt transport in coastal aquifer systems. A two-layer heterogeneous coastal aquifer system composed of a lower sand layer (aquifer) and an upper clay layer (aquitard) and a corresponding single-layer homogeneous coastal aquifer system composed of an equivalent lumped material are simulated to evaluate impacts of layered heterogeneity on seawater intrusion. In addition, a continuous groundwater pumping scheme and two different periodical groundwater pumping schemes, which withdraw the same amount of groundwater during the total simulation time, are applied to the above two coastal aquifer systems to evaluate impacts of groundwater pumping schemes on seawater intrusion. The results of the numerical simulations show that the periodical groundwater pumping schemes have more significant adverse influences on groundwater flow and salt transport not only in the lower sand layer but also in the upper clay layer, and groundwater salinization becomes more intensified spatially and temporally as the pumping intensity is higher under the periodical groundwater pumping schemes. These imply that the continuous groundwater pumping scheme may be more suitable to minimize groundwater salinization due to seawater intrusion. The results of the numerical simulations also show that groundwater salinization in the upper clay layer occurs significantly different from that in the lower sand layer under the periodical groundwater pumping schemes. Such differences in groundwater salinization between the two adjacent layers may result from layered heterogeneity of the layered coastal aquifer system.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.27 no.4B
• /
• pp.379-387
• /
• 2002

In this paper, we present a procedure to obtain the transient scattering response from three-dimensional arbitrarily shaped and closed conducting bodies using time-domain magnetic field integral equation (TD-MFIE) with triangular patch functions. This approach results in accurate and comparably stable transient responses from conducting scatterers. Detailed mathematical steps are included, and several numerical results are presented and compared with results from a time-domain electric field integral equation (TD-EFIE) and the inverse courier transform solution of the frequency domain results.