• The KIPS Transactions:PartB
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• v.11B no.7 s.96
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• pp.793-802
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• 2004

Users in 3D virtual environment get limited information which contains mostly images. It is the main reason for users getting lost during their Navigation. Various studies of Navigation-Aid have been done in order to solve this problem. In this study, we applied Topic Maps, which is one of semantic Web techniques, to the navigation in a 3D virtual environment. Topic Maps construct semantic linking maps through defining the relations between topics. Experiments in which Topic Map based Navigation-Aid was applied have shown that the Navigation-Aid was effective when the subjects find a detailed target rather than a highly represented one. Also, offering information around the target helped the users to find the target when they navigated without having specific targets.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2007.04a
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• pp.421-425
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• 2007

The application of 3 dimensional virtual reality continuously pursues 3 dimensional system implementation in geographical information system, and is applied and studied in various fields like visualization, simulation, and 3 dimensional analysis. Orthoimage produced to construct basic data of virtual city is evaluated in accuracy, to fall in allowable error of the specification of image map generation. In this paper, 3 dimensional virtual city is constructed and evaluated around Bucheon University using 3 dimensional virtual reality technique and digital photogrammetry. Consequently, the constructed 3 dimensional virtual city around Bucheon University can visualize 3 dimensional reality, to help making decision. It can be substituted for existed 2 dimensional GIS in public and private sectors, and be helpful to decision makers.

• JSTS:Journal of Semiconductor Technology and Science
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• v.12 no.2
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• pp.127-138
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• 2012

In this paper, we propose a real-time virtual re-convergence hardware platform especially to reduce the visual fatigue caused by stereoscopy. Our unique idea to reduce visual fatigue is to utilize the virtual re-convergence based on the optimized disparity-map that contains more depth information in the negative disparity area than in the positive area. Our virtual re-convergence hardware platform, which consists of image rectification, disparity estimation, depth post-processing, and virtual view control, is realized in real time with 60 fps on a single Xilinx Virtex-5 FPGA chip.

• Journal of the Korean Society of Safety
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• v.24 no.6
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• pp.1-6
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• 2009

This study describes a construction procedure of 3D virtual space using the NGIS data and its application to simulation. 3D space topography is modeled by using DEM consisted with triangular regular network. The elevations of nodal points of DEM are calculated through the interpolation with contour line and elevation points from the NGIS. Also, data for 2D roads and their environments, such as trees, lamps, and traffic signals, were extracted from the NGIS and projected on the DEM surfaces to get 3D virtual space. To give a reality to 3D virtual space and accelerate its graphic speed, data were converted into the directX format. It is believed that the virtual space constructed in this work can be applicable to the ubiqutous because DEM data can be converted to the AutoCAD format and ASCII code.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.25 no.5
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• pp.389-395
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• 2012

U-City has been promoted nation-wide by development of recent IT technology. This paper studied the concept of 3D-virtual city in order to realize the current Ubiquitous City(U-City) efficiently, and to manage all the RFID/USN monitoring data in the real U-City. 3D-Virtual City is the concept of the reproduction of real world U-City, for embodying Ubiquitous technology while using Digital map, satellite image, VRML(Virtual Reality Modeling Language). U&V-City is the four-dimensional future city that real-time wire/wireless communication network and 3D-web GIS shall be connected that massive database, intelligent service be perceived through employing EAI(External Authoring Interface) that provides HTML&JAVA, and interface for efficient removal/process of massive information/ service and also by employing GPS/LBS/Navigation in support of world-wide orientation concept, and RTLS(Real Time Location System).

• Journal of Biomedical Engineering Research
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• v.24 no.2
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• pp.77-82
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• 2003

Virtual colonoscopy is a non-invasive computerized procedure to detect polyps by examining the colon from a CT data set. To fly through the inside of colons. the extraction of a suitable flight-path is necessary to Provide the viewpoint and view direction of a virtual camera. However. manual path extraction by Picking Points is a very time-consuming and difficult task due 1,c, the long and complex shape of colon. Also, existing automatic methods are computationally complex. and tend to generate an improper and/or discontinuous path for complicated regions. In this paper, we propose a fast flight-path generation algorithm using the distance and order maps. The order map Provides all Possible directions of a path. The distance map assigns the Euclidean distance value from each inside voxel to the nearest background voxel. By jointly using these two maps. we can obtain a proper centerline regardless of thickness and curvature of an object. Also, we Propose a simple smoothing technique that guarantees not to collide with the surface of an object. The phantom and real colon data are used for experiments. Experimental results show that for a set of human colon data, the proposed algorithm can provide a smoothened and connected flight-path within a minute on an 800MHz PC. And it is proved that the obtained flight-Path provides successive volume-rendered images satisfactory for virtual navigation.

• Journal of Convergence for Information Technology
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• v.8 no.6
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• pp.335-341
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• 2018

This paper is a study on map contents to be embedded in a new type of mobile device that combines 2D information and 3D information by combining 2D information with augmented reality technology. We also describe the planning and production of a 3D map application called 'NSU AR Map' using Unity3D engine to help understand this paper. 'NSU AR Map' is a map application that enables accurate identification of user's location and real-world view through 360 View. Based on the experience gained during the process of 3D map application, this paper will present how 3D technologies and augmented reality technologies are applied to new map applications and how they can be developed in the future.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.2
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• pp.522-541
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• 2016

Network virtualization provides an effective way to overcome the Internet ossification problem. As one of the main challenges in network virtualization, virtual network embedding refers to mapping multiple virtual networks onto a shared substrate network. However, existing heuristic embedding algorithms evaluate the embedding potential of the nodes simply by the product of different resource attributes, which would result in an unbalanced embedding. Furthermore, ignoring the hops of substrate paths that the virtual links would be mapped onto may restrict the ability of the substrate network to accept additional virtual network requests, and lead to low utilization rate of resource. In this paper, we introduce and extend five node attributes that quantify the embedding potential of the nodes from both the local and global views, and adopt the technique for order preference by similarity ideal solution (TOPSIS) to rank the nodes, aiming at balancing different node attributes to increase the utilization rate of resource. Moreover, we propose a novel two-stage virtual network embedding algorithm, which maps the virtual nodes onto the substrate nodes according to the node ranks, and adopts a shortest path-based algorithm to map the virtual links. Simulation results show that the new algorithm significantly increases the long-term average revenue, the long-term revenue to cost ratio and the acceptance ratio.

• The Journal of Korea Robotics Society
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• v.4 no.4
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• pp.298-304
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• 2009

This paper describes an algorithm that improves 3D reconstruction result using a multi-sensor fusion disparity map. We can project LRF (Laser Range Finder) 3D points onto image pixel coordinatesusing extrinsic calibration matrixes of a camera-LRF (${\Phi}$, ${\Delta}$) and a camera calibration matrix (K). The LRF disparity map can be generated by interpolating projected LRF points. In the stereo reconstruction, we can compensate invalid points caused by repeated pattern and textureless region using the LRF disparity map. The result disparity map of compensation process is the multi-sensor fusion disparity map. We can refine the multi-sensor 3D reconstruction based on stereo vision and LRF using the multi-sensor fusion disparity map. The refinement algorithm of multi-sensor based 3D reconstruction is specified in four subsections dealing with virtual LRF stereo image generation, LRF disparity map generation, multi-sensor fusion disparity map generation, and 3D reconstruction process. It has been tested by synchronized stereo image pair and LRF 3D scan data.

• Journal of the Korea Society of Computer and Information
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• v.24 no.8
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• pp.137-142
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• 2019

This paper proposed bitmap based spatial data transmission scheme in need of rapid transmission through network in mobile environment that use and creation of data are frequently happen. Former researches that used clustering algorithms, focused on providing service using spatial data can cause delay since it doesn't consider the transmission speed. This paper guaranteed rapid service for user by convert spatial data to bit, leads to more transmission of bit of MTU, the maximum transmission unit. In the experiment, we compared arithmetically default data composed of 16 byte and spatial data converted to bitmap and for simulation, we created virtual data and compared its network transmission speed and conversion time. Virtual data created as standard normal distribution and skewed distribution to compare difference of reading time. The experiment showed that converted bitmap and network transmission are 2.5 and 8 times faster for each.