• International Journal of CAD/CAM
• /
• v.6 no.1
• /
• pp.29-40
• /
• 2006

The paper presents an optimization system which integrates a parametric design tool, 3D diffraction-radiation analysis and hydrodynamic performance assessment based on short and long term wave statistics. Controlled by formal optimization strategies the system is able to design offshore structure hulls with superior seakeeping qualities. The parametric modeling tool enables the designer to specify the geometric characteristics of the design from displacement over principal dimensions down to local shape properties. The computer generates the hull form and passes it on to the hydrodynamic analysis, which computes response amplitude operators (RAOs) for forces and motions. Combining the RAOs with short and long-term wave statistics provides a realistic assessment of the quality of the design. The optimization algorithm changes selected shape parameters in order to minimize forces and motions, thus increasing availability and safety of the system. Constraints ensure that only feasible designs with sufficient stability in operation and survival condition are generated. As an example the optimization study of a semisubmersible is discussed. It illustrates how offshore structures can be optimized for a specific target area of operation.

• International Journal of CAD/CAM
• /
• v.5 no.1
• /
• pp.69-81
• /
• 2005

As collaborative design and configuration design gain increasing importance in product development, it becomes essential to exchange parametric CAD models among participants. Parametric CAD models can be represented and exchanged in the form of a macro file or a part file that contains the modeling history of a product. The modeling history of a parametric CAD model contains feature specifications and each feature has selection information that records the name of the referenced topological entities. Translating this selection information requires solving the problems of how to identify the referenced topological entities of a feature (persistent naming problem) and how to convert the selection information into the format of the receiving CAD system (naming mapping problem). The present paper introduces the problem of exchanging parametric CAD models and proposes a solution to naming mapping.

• Journal of the Korean Geographical Society
• /
• v.51 no.2
• /
• pp.219-233
• /
• 2016

In social science fields, statistical models are used almost exclusively for causal explanation, and explanatory modeling has been a mainstream until now. In contrast, predictive modeling has been rare in the fields. Hence, we focus on constructing the predictive non-parametric model, instead of the explanatory model. Gangnam-gu, Seoul was chosen as a study area and we collected single-family house sales data sold between 2011 and 2014. We applied non-parametric models proposed in machine learning area including generalized additive model(GAM), random forest, multivariate adaptive regression splines(MARS) and support vector machines(SVM). Models developed recently such as MARS and SVM were found to be superior in predictive power for house price estimation. Finally, spatial autocorrelation was accounted for in the non-parametric models additionally, and the result showed that their predictive power was enhanced further. We hope that this study will prompt methodology for property price estimation to be extended from traditional parametric models into non-parametric ones.

• Journal of the Computational Structural Engineering Institute of Korea
• /
• v.31 no.1
• /
• pp.1-8
• /
• 2018

The purpose of this study is to implement modeling by applying the parametric technique to the atypical trusses of rigid retractable large space structures. The retractable large space structure requires a lot of time and skill in modeling nonlinear shapes or generating, interpreting, and reviewing many models by alternative. To solve these problems, we introduce firstly parametric modeling tool, secondly, we analyze the connection of atypical three-dimensional trusses of a rigid retractable large-space structure, and finally model it as parametric components of the developed trusses. Therefore, it is a future study to make effective modeling of the openable roof by developing the components that can realize the modeling of the truss classified by the opening and closing method, respectively.

• Journal of KIBIM
• /
• v.3 no.3
• /
• pp.19-28
• /
• 2013

In Korea highway bridges, most piers are the type of one-column or multi-column ones. So, in this study, under an environment applying BIM so fast, to activate researches on two-column piers subjected to bidirectional seismic loading, a 3D parametric modeling method was selected when the model of two-column piers and one-column piers were formed. Also, interface module between input data in structural analysis and 3D model of RC pier was developed. The module can create the input data for non-linear structural analysis like material, geometric properties and additional coefficients.

• Korean Journal of Computational Design and Engineering
• /
• v.3 no.4
• /
• pp.293-303
• /
• 1998

The objective of this study is to develop a PC level freeform surface modeling system which explicitly represents information of part geometry. Surface modeler uses nonuniform rational B-spline (NURBS) function with nonuniform knot vector for the flexible modeling work. The results of this study are as follows. 1) By implementation surface modeler through applying representation scheme proposed to represent free-form surface explicity, the technical foundation to develop free-from surface modeling system using parametric method. 2) Besides the role to model geometric shape of a surface, geometric modeler is developed to model arbitrary geometric shape. By doing this, the availability of the modeling system is improved. Geometric modeler can be utilized application fields such as collision test of tool and fixture, and tool path generation for NC machine tool.

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2021.05a
• /
• pp.157-158
• /
• 2021

Recently, there have been a growing number of cases using precast concrete construction methods to efficiently carry out construction projects. In order to efficiently carry out PC construction, it is necessary to establish a production plan of PC components that effectively reflect various design alternatives during the initial design stage. Because the production plan of PC components is based on productivity of PC members, the use of PC production simulations that can effectively predict productivity for design alternatives is necessary. Therefore, this paper propose a method to efficiently generate design alternatives which is necessary to perform to production simulations using parametric modeling techniques and BIM.

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2023.05a
• /
• pp.163-164
• /
• 2023

The technical proposal bidding system emphasizes the evaluation of the construction company's technical capabilities, with the aim of improving the quality and cost-effectiveness of the construction. However, in the VE analysis and proposal process for technical proposal bidding, the ideas are often reused from similar past construction projects, and the application of new construction technologies/methods is often lacking. Therefore, this study proposes a methodology for managing VE proposal information by integrating it into a BIM model using parametric modeling. This research developed database based on the existing VE proposals and new construction technology/method information from the Korea Institute of Civil Engineering and Building Technology. And by using parametric modeling, the proposed method integrate the VE database with BIM model. The methodology proposed in this study is expected to improve the reliability and effectiveness of VE-related idea proposals in technical proposal bidding.

• Korean Journal of Computational Design and Engineering
• /
• v.11 no.3
• /
• pp.164-171
• /
• 2006

As collaborative design and configuration design are of increasing importance in product development, it becomes essential to exchange the feature and parametric CAD models among participants. A history-based parametric method has been proposed and implemented. But each translator which exchanges the feature and parametric information tends to be heavy because to implement duplicated functions such as the identification of the selected geometries, mapping between features which have different attributes. Furthermore. because the history-based parametric translator uses the procedural model as the neutral format, which is the XML macro file, the history-based parametric translators need a geometric modeling kernel to generate an internal explicit geometric model. To ease the problem, we implemented a shared integration platform, the TransCAD. The TransCAD separates translators from the XML macro files. The translators for various CAD systems need to communicate with only the TransCAD. To support the communication with the TransCAD, we exposed the functions of the TransCAD by using the Automation APIs, which is developed by Microsoft. The Automation APIs of the TransCAD consist of the part modeling functions, the data extraction functions, and the utility functions. Each translator uses these functions to translate a parametric CAD model from the sending CAD system into the XML format, or from the in format into the model of the receiving CAD system This paper introduces what the TransCAD is and how it works for the exchange of the feature and parametric models.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.18 no.4
• /
• pp.92-98
• /
• 2010

Virtual ground modeling is one of key topic for real-time vehicle dynamic simulation. This paper discusses about the virtual 3D road modeling process using parametric surface concept. General road data is a type of lumped position vector so interpolation process is required to compute contact of internal surface. The parametric surface has continuity and linearity within boundaries and functions are very simple to find out contact point. In this paper, the parametric surface formula is adopted to road modeling to calculate road hight. Position indexing method is proposed to reduce memory size and resource possession, and a simple mathematical method for contact patch searching is also proposed. The developed road process program is tested in dynamic driving simulation on off-road. Conclusively, the new virtual road program shows high performance of road hight computation in vast field of off-road simulation.