• 한국CDE학회논문집
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• 제10권5호
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• pp.303-313
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• 2005

This paper proposes a generalized NURBS model, called Volumetric NURBS or VNURBS for representing volumetric objects with multiple attributes embedded in multidimensional space. This model provides a mathematical framework for modeling complex structure of heterogeneous objects and analyzing inside of objects to discover features that are directly inaccessible, for deeper understanding of complex field configurations. The defining procedure of VNURBS, which explains two directional extensions of NURBS, shows VNURBS is a generalized volume function not depending on the domain and its range dimensionality. And the recursive a1gorithm for VNURBS derivatives is described as a computational basis for efficient and robust volume modeling. In addition, the specialized versions of VNURBS demonstrate that VNURBS is applicable to various applications such as geometric modeling, volume rendering, and physical field modeling.

• 한국생산제조학회지
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• 제22권3호
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• pp.394-401
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• 2013

A new Rockwell hardness (HRC) model using a volumetric parameter by a least square and fractal interpolation method is suggested. The results are also investigated in comparison to real measured hardness data. For this purpose, the measurement of an indented volume is performed using a confocal laser scanning microscope (CLSM), and the captured height encoded image (HEI) is used as an original surface for the calculation of the indented volume. After configuring the surface, the constructed volume is calculated and used as an independent variable for HRC hardness modeling. The hardness model is established using an experimental modeling technique involving a least square algorithm and fractal interpolating model, and this suggested model can be used to reliably predict the Rockwell hardness. These techniques can also be applied to the modeling of the Brinnell and Vickers hardnesses using a volumetric variable.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2008년 영문 학술대회
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• pp.243-246
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• 2008

This paper is to consider analytical thermodynamic modeling of bipropellant propulsion system. The objective of thermodynamic modeling is to predict thermodynamic conditions such as pressures, temperatures and densities in the pressurant tank and the propellant tank in which heat and mass transfer occur. In this paper also it shows analytic equations that calculate the evolution of ullage volume and interface areas. Since the ullage interface areas are time-varying,(the liquid propellant volume decreases as the rocket engine is firing; the change of ullage volume correspond to the change of liquid propellant volume) for a numerical convenience non-dimensionalized correlations are commonly used in most literatures with limitations; a few percentages of inherent error. The analytic equations are derived from analytic geometry, subsequently without inherent error. Those equations are important to calculate the heat transfer areas in the heat transfer equations. It presents the comparison result of both analytic equations and correlation method.

• 한국CDE학회논문집
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• 제16권3호
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• pp.178-186
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• 2011

Static CAD models are the CAD models that do not have feature information and modeling history. These static models are generated by translating CAD models in a specific CAD system into neutral formats such as STEP and IGES. When a CAD model is translated into a neutral format, its precious feature information such as feature parameters and modeling history is lost. Once the feature information is lost, the advantage of feature based modeling is not valid any longer, and modification for the model is purely dependent on geometric and topological manipulations. However, the capabilities of the existing methods to modify static CAD models are limited, Direct modification methods such as tweaking can only handle the modifications that do not involve topological changes. There was also an approach to modify static CAD model by using volume decomposition. However, this approach was also limited to modifications of protrusion features. To address this problem, we extend the volume decomposition approach to handle not only protrusion features but also depression features in a static CAD model. This method first generates the model that contains the volume of depression feature using the bounding box of a static CAD model. The difference between the model and the bounding box is selectively decomposed into so called the feature volume and the base volume. A modification of depression feature is achieved by manipulating the feature volume of the static CAD model.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제7권9호
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• pp.2232-2245
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• 2013

The present study proposes efficient procedural modeling methods for enabling the growth and creation of various trees with minimal user control. Growth volume algorithms are utilized in order to easily and effectively calculate many parameters that determine tree growth, including branch propagation. Procedural methods are designed so that users' interactive control structures can be applied to these algorithms to create unique tree models efficiently. First, through a two-line-based interactive growth volume control method, the growth information that determines the overall shape of the tree is intuitively adjusted. Thereafter, independent branch control methods designed to control individual branches are added to the growth deformation in order to enable the growth of unique trees. Whether the growth processes of desired trees can be easily and intuitively controlled by the proposed method is verified through experiments. Methods that can apply the proposed methods are also verified.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2005년도 춘계 학술발표회 논문집
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• pp.439-444
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• 2005

Shotcrete lining is likely to be deteriorated due to the ground water which the lining is exposed to. Some tunnel collapses seemed to be affected by shotcrete degradation were reported. But there isn't any assessment method of shotcret long-term degradation. So, Experimental technology for shotcrete long-term degradation modeling was developed in this study. The shotcrete long-term degradation modeling, developed in other study in Korea Institute of Construction Technology, require the time-history of volume change. Digital strain observation system was used to acquire the time-history of volume change. To verify the Strain Observation Digital System, the measurement using the system was compared to the one using a micrometer. Through this process, The experiment for shotcrete long-term degradation modeling was set up.

• 한국CDE학회논문집
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• 제10권5호
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• pp.314-327
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• 2005

This paper describes the volumetric data modeling and analysis methods that employ volumetric NURBS or VNURBS that represents heterogeneous objects or fields in multidimensional space. For volumetric data modeling, we formulate the construction algorithms involving the scattered data approximation and the curvilinear grid data interpolation. And then the computational algorithms are presented for the geometric and mathematical analysis of the volume data set with the VNURBS model. Finally, we apply the modeling and analysis methods to various field applications including grid generation, flow visualization, implicit surface modeling, and image morphing. Those application examples verify the usefulness and extensibility of our VNUBRS representation in the context of volume modeling and analysis.

• Fisheries and Aquatic Sciences
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• 제14권2호
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• pp.138-147
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• 2011

Modeling fishing-gear systems is essential to better understand the factors affecting their movement and for devising strategies to control movement. In this study, we present a generalized mathematical modeling methodology to analyze fishing gear and its various components. Fishing gear can be divided into a finite number of elements that are connected with flexible lines. We use an algorithm to develop a numerical method that calculates precisely the shape and movement of the gear. Fishinggear mathematical models have been used to develop software tools that can design and simulate dynamic movement of novel fishing-gear systems. The tool allowed us to predict the shape and motion of the gear based on changes in operation and gear design parameters. Furthermore, the tool accurately calculated the swept volume of towed gear and the surrounding volume of purse-seine gear. We analyzed the fished volume for trawl and purse-seine gear and proposed a new definition of fishing effort, incorporating the concept of fished space. This method may be useful for quantitative fishery research, which requires a good understanding of the selectivity and efficiency of fishing gear used in surveys.

• 한국정보처리학회논문지
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• 제6권4호
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• pp.1081-1089
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• 1999

볼륨 데이터 모델링은 삼차원 공간 내부에 존재하는 데이터 사이의 관계를 함수로 표현하는 것이다. 볼륨 데이터를 기하학적을 모델링하면 볼륨을 복셀로 분할하지 않고 서피스 렌더링 기법을 이용하여 가시화할 수 있어, 고속 처리가 가능해지며 정보를 저장하기 위한 메모리의 용량도 적어지는 이점이 있다. 본 논문에서는 웨이브렛(wavelets) 변환과 사면체 분할(tetrahedrization)을 기반을 볼륨 데이터를 모델링하는 기법을 제안하고, 이것을 이용하여 프로토타입 시스템을 구현하여 평가하였다. 본 모델링 기법은 웨이브렛 변환과 사면체 분할의 특성을 이용할 수 있어 많은 양의 데이터의 압축이 가능했으며, 애매성도 발생하지 않았다. 본 모델링 기법에서는 전체 데이터의 13%만을 이용하여 모델링 하였음에도 불구하고 마칭큐브 알고리즘에 떨어지지 않는 영상을 생성하였다.

• 한국지능시스템학회논문지
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• 제22권3호
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• pp.294-299
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• 2012

본 논문은 단체 급식용 동결 생선을 일정한 중량으로 절단하기 위하여, 생선의 외형 및 부피 예측 모델링 기법을 제안하고, 실제 생선에 대한 절단 실험을 수행한다. 단체 급식용 동결 생선은 동결 하는 시점에서 발생한 생선의 휘어짐과, 머리를 절단하고 내장을 제거할 때에 발생하는 중공이 존재한다. 이외에도 동결의 영향으로 나타나는 표면의 반짝임이나 수분 량에 따른 무게의 차이로 인해 측정 및 추정의 어려움이 크다. 따라서 동결 생선의 외형과 부피를 정확히 추정하기 위해서는 상기의 특성과 문제점들을 반영한 복합적인 추정 알고리즘이 필요하다. 이를 위해, 중공 예측, 신경망을 이용한 꼬리부분 패턴 분류 및 모델링, 그리고 적분 기법 기반의 부피 예측 알고리즘을 각각 제안하고, 삼치, 꽁치, 고등어 3종류의 생선에 대해서 3차원 계측, 부피 예측 및 절단 실험을 수행한다.