• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.36 no.6
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• pp.545-554
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• 2018

As the map paradigm shifts from analog to digital, the LOD (Level Of Detail) of spatial information needs to be redefined. In this study, we propose 4- dimensional indoor LOD model which can be used in digital map environment. For this purpose, the limitation of the previous research is derived through study of related works, and based on this, four different LODs are defined such PLOD (Position accuracy LOD) based on position accuracy, GLOD (Geometric LOD) based on shape representation, CLOD (Complete LOD) based on generalization, and SLOD (Semantic LOD) based on theme accuracy. In addition, we describe the relationships among the four different LODs, and explain how to express the indoor LOD using the four different LODs and show examples. In the future, the case studies of indoor LOD adoption for various indoor services and the study of method for applying CLOD and SLOD to each feature should be performed to verify the feasibility and validity of proposed indoor LOD.

• Korean Journal of Computational Design and Engineering
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• v.11 no.4
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• pp.315-325
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• 2006

It is very often necessary to search for similar parts during designing a new product because its parts are often easily designed by modifying existing similar parts. In this way, the design time and cost can be reduced. Thus it would be nice to have an efficient similarity comparison algorithm that can be used anytime in the design process. There have been many approaches to compare shape similarity between two solids. In this paper, two parts represented in B-Rep is compared in two steps: one for overall appearances and the other for detail features. In the first step, geometric information is used in low level of detail for easy and fast pre-classification by the overall appearance. In the second step, feature information is used to compare the detail shape in high level of detail to find more similar design. To realize the idea above, a multi resolution algorithm is proposed so that a given solid is described by an overall appearance in a low resolution and by detail features in high resolution. Using this multi-resolution representation, parts can be compared based on the overall appearance first so that the number of parts to be compared in high resolution is reduced, and then detail features are investigated to retrieve the most similar part. In this way, computational time can be reduced by the fast classification in the first step while reliability can be preserved by detail comparison in the second step.

• 한국HCI학회:학술대회논문집
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• 2007.02a
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• pp.963-968
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• 2007

In this paper introduce Standard 3D object(Bounding-Volume). In 3D game very efficient control algorithm Using collision detection which controls the convenient of a game based on Standard 3D object specially collision-detection. This algorithm is designed LOD(Level-of-Detail) using Dynamic-Hierarchies of collision detection efficiency improvement in 3D object.

• Korean Journal of Cognitive Science
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• v.6 no.2
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• pp.47-79
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• 1995

Since the early age of computer graphics, facial animation has been applied to various fields, and nowadays it has found several novel applications such as virtual reality(for representing virtual agents), teleconference, and man-machine interface.When we want to apply facial animation to the system with multiple participants connected via network, it is hard to animate facial expression as we desire in real-time because of the size of information to maintain an efficient communication.This paper's major contribution is to adapt 'Level-of-Detail'to the facial animation in order to solve the above problem.Level-of-Detail has been studied in the field of computer graphics to reperesent the appearance of complicated objects in efficient and adaptive way, but until now no attempt has mode in the field of facial animation. In this paper, we present a systematic scheme which enables this kind of adaptive control using Level-of-Detail.The implemented system can generate speech synchronized facial expressions with various types of user input such as text, voice, GUI, head motion, etc.

• Journal of Korea Multimedia Society
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• v.5 no.4
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• pp.361-371
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• 2002

An efficient access technique is one of the most Important requirements in GIS. Using level -of-detailed data, we can access spatial data efficiently, because of no access to the fully detailed spatial data. Previous spatial access methods do not access data with level of detail efficiently. To solve it, a few spatial access methods for spatial data with level of detail, are known. However these methods support only a few kinds of data with level of detail, i.e, data through selection and simplification operations. For the effects, we propose a new spatial indexing method supporting fast searching in all kinds of data with level of detail. In the proposed method, the collection of indexes in its own level are integrated into a single index structure. Experimental results show that our method offers both no data redundancy and high search performance.

• Journal of KIISE:Computer Systems and Theory
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• v.34 no.3
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• pp.124-131
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• 2007

Research field on crowd animation can be classified into two major categories. One is to offer realism of the crowd motion and the other is to improve speed of the animation. For the last decade, a lot of research on realism and behavior of crowd have been presented. But lately, research on improving speed seems like more interesting. Therefore, in this paper, we conducted an experiment to analyze what is the main bottleneck of crowd animation. As the result, we find out one of the most important bottleneck is the number of joints transformed in each animation frame. In order to resolve this problem we propose a novel level-of-detail technique 'motion level-of-detail', which is a joint-reduction technique operated in the pre-processing time. We used a non-linear optimization, SQP (sequential quadric programming), to generate the low detailed motions.

• Journal of KIBIM
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• v.7 no.4
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• pp.8-20
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• 2017

When it comes to set up the BIM through the reverse engineering, the level of detail(LoD) required for finalized outcomes is different from each purpose. Therefore, it is necessary to establish some concrete criteria which describe the definition of LoDs on 3D modeling for the purpose of each reverse engineering. This research shows the criteria of the 1) positional accuracy, 2) generalization level, 3) scale level, 4) scope of description, and 5) the area available for application by classifying LoD from 1 to 6 on 3D modeling for each purpose of reverse engineering. Moreover, through applying those criteria for the 3D point cloud dataset of building made by terrestrial LiDAR, this research finds out the working hour of 3D modeling of reverse engineering by each LoDs according to defined LoD criteria for each level. It is expected that those findings, how those criteria of LoD on reverse engineering are utilized for modeling-workers to decide whether the outcomes can be suitable for their budget, applicable fields or not, would contribute to help them as a basic information.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.32 no.2
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• pp.143-151
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• 2014

As the interest in indoor space increases, the demands for various services based on indoor space is increasing. With the demands, to construct spatial information for indoor space is also required, but there is not defined the LOD(Level of Detail) for indoor spatial data. Therefore, in this paper we classified data for indoor space data construction, and then we defined the accuracy and detail about the level of detail to provide suitable application services according to the type and representation method of each data. Most previous researches are focus on the geometrical representation, but in this paper we define a indoor LOD model based on type and representation method of data. In addition, we present applicable services with proposed LOD model and suggest a guideline for construction and application of indoor space.

• Journal of the Korea Institute of Military Science and Technology
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• v.23 no.6
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• pp.542-553
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• 2020

Virtual world and simulation need large scale map rendering. However, rendering too many vertices is a computationally complex and time-consuming process. Some game development companies have developed 3D LOD objects for high-speed rendering based on distance between camera and 3D object. Terrain physics simulation researchers need a way to recognize the original object shape from 3D LOD objects. In this paper, we proposed simply automatic LOD framework using point cloud data (PCD). This PCD was created using a 6-direct orthographic ray. Various experiments are performed to validate the effectiveness of the proposed method. We hope the proposed automatic LOD generation framework can play an important role in game development and terrain physic simulation.

• The Journal of the Korea institute of electronic communication sciences
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• v.4 no.3
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• pp.190-196
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• 2009

A new time adapted threshold using the standard deviations of Wavelet coefficients after Wavelet transform by frame scale is proposed. The time adapted threshold is set up using the sum of standard deviations of Wavelet coefficient in level 3 approximation and weighted level 1 detail. Level 3 approximation coefficients represent the voiced sound with low frequency and level 1 detail coefficients represent the unvoiced sound with high frequency. After reducing noise by soft thresholding with the proposed time adapted threshold, there are still residual noises in silent interval. To reduce residual noises in silent interval, a detection algorithm of silent interval is proposed. From simulation results, it can be noticed that SNR and MSE of the proposed algorithm are improved than those of Wavelet transform and than those of Wavelet packet transform.