• 로봇학회논문지
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• 제2권3호
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• pp.275-281
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• 2007

This paper presents a motion planning strategy for legged robots using locomotion primitives in the complex 3D environments. First, we define configuration, motion primitives and locomotion primitives for legged robots. A hierarchical motion planning method based on a combination of 2.5 dimensional maps of the 3D workspace is proposed. A global navigation map is obtained using 2.5 dimensional maps such as an obstacle height map, a passage map, and a gradient map of obstacles to distinguish obstacles. A high-level path planner finds a global path from a 2D navigation map. A mid-level planner creates sub-goals that help the legged robot efficiently cope with various obstacles using only a small set of locomotion primitives that are useful for stable navigation of the robot. A local obstacle map that describes the edge or border of the obstacles is used to find the sub-goals along the global path. A low-level planner searches for a feasible sequence of locomotion primitives between sub-goals. We use heuristic algorithm in local motion planner. The proposed planning method is verified by both locomotion and soccer experiments on a small biped robot in a cluttered environment. Experiment results show an improvement in motion stability.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2008년도 International Symposium on Remote Sensing
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• pp.274-276
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• 2008

At the stage of content convergence into cell phone, technologies for geo-spatial information sharing and searching are being developed. Currently, 2D portable navigation map for mobile navigation is provided by communication companies, but geobrowers for 3D geo-information in cell phone are under developing. In this study, 3D feature transformation among X3D-M3G-KML, on mobile and web environments, is dealt with as the first stage for the further mobile 3D web application. As well, it is possible to real-time interoperable 3D geo-information exchange issues within both environments.

• Journal of Positioning, Navigation, and Timing
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• 제9권4호
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• pp.367-378
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• 2020

This paper introduces the development of the iterative multiple signal classification (MUSIC)-based direction-of-arrival (DOA) estimation system using a rotator that can control the direction of antenna for the global navigation satellite system (GNSS) interference. The system calculates the spatial spectrum according to the noise eigenvector of all dimensions to measure the number of signals (NOS). Also, to detect the false peak, the system adjusts the array antenna's direction and checks the change's peak angles. The phase delay and gain correction values for system calibration are calculated in consideration of the chamber's structure and the characteristics of radio waves. The developed system estimated DOAs of interferences located about 1km away. The field test results show that the developed system can estimate the DOA without NOS information and detect the false peak even though the inter-element spacing is longer than the half-wavelength of the interference.

• 한국컴퓨터그래픽스학회논문지
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• 제18권2호
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• pp.63-72
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• 2012

BIM(Building Information Modeling)과 같은 기법이 건축물 생산 과정에 널리 사용되면서 건축 모델을 현실감 있게 체험할 수 있는 방법의 필요성이 커지고 있다. 본 논문에서는 시각적 인지를 고려한 가상 건축물의 스테레오 내비게이션 방법을 제안한다. 먼저 스테레오 건축물을 내비게이션할 때 발생할 수 있는 시각적 불편함에 대해 분석하고, 이를 해결하기 위해 가상 카메라 간격을 자동으로 조절하는 방법을 개발한다. 또한 각 사용자의 깊이감에 대한 최소한의 자극 차이(Just Noticeable Difference)를 측정하고 그 결과를 가상 카메라의 간격과 움직임을 조절하는데 적용한다. 제안된 방법은 사용자에게 적합한 스테레오 콘텐츠를 생성함으로써 다양한 건축 응용에 사용될 수 있다.

• 센서학회지
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• 제16권3호
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• pp.220-228
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• 2007

For many applications particularly in navigation system, a three-dimensional representation improves the usability of information. This paper introduces 3D Graphical User Interface (GUI) of indoor location tracking system, 3D Navigation View. The application provides users a 3D visualization of the indoor environments they are exploring, synchronized with the physical world through spatial information obtained from indoor location tracking system. It adopts widely used Virtual Reality Modeling Language (VRML) to construct, represent, distribute and render 3D world of indoor environments over Internet. Java, an all-purpose programming language is integrated to comprehend spatial information received from indoor location tracking system. Both are connected through an interface called External Authoring Interface (EAI) provided by VRML. Via EAI, Java is given the authority to access and manipulate the 3D objects inside the 3D world that facilitates the indication of user's position and viewpoint in the constructed virtual indoor environments periodically.

• 디자인학연구
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• 제16권3호
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• pp.71-80
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• 2003

가상현실 분야는 이제 대중화시대를 맞이하고 있다. 데스크탑 가상현실 산업은 다양한 Web VR 애플리케이션을 중심으로 급속히 성장하고 있는 추세이다. 3차원 가상공간에서 사용자 네비게이션의 수행은 가상의 공간에 설정된 논리적 구조를 인지하고 설정된 상호작용을 이해하며 길을 찾아가는 복잡한 과정이다. 그 것은 사용자가 임으로 설정하는 과정이 아니고 기획단계에서 면밀히 디자인되고 설계된 기술적, 기법적 그리고 개념적 과정인 것이다. 이에 따라 본 논고에서는 3차원 가상공간에서의 상호작용적 네비게이션과 관련된 기술적, 기법적, 그리고 개념적 기초이론들을 총체적으로 고찰하고 있다.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2014년도 추계학술대회
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• pp.341-343
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• 2014

3D 지리정보 통합 플렛폼을 활용하여 해양교통시설 정보 및 이를 운영하기 위한 다양한 부가정보(기상, 낙뢰, 지진, AIS 등)를 매쉬업하여 표출함으로서 해양교통시설을 효과적으로 운영관리하고 이를 활용하여 서비스 이용자 접근성을 보다 표리하게 제공할 수 있는 방안을 제시하고자 한다.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2006년도 International Symposium on GPS/GNSS Vol.2
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• pp.71-76
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• 2006

With the rapid development of spatial infrastructure in US, Europe, Japan, China and India, there is no doubt that the next generation Global Navigation Satellite System (GNSS) will improve the integrity, accuracy, reliability and availability of the position solution. GNSS is becoming an essential element of personal, commercial and public infrastructure and consequently part of our daily lives. However, the applicability of GPS in supporting a range of location-sensitive applications such as location based services in an urban environment is severely curtailed by the interference of the 3D urban settings. To characterize and gain in-depth understanding of such interferences and to be able to provide location-based optimization alternatives, a high-fidelity 3D urban model of Melbourne CBD built with ArcGIS and large scale high-resolution spatial data sets is used in this study to support a comprehensive simulation of current and future GNSS signal performance, in terms of signal continuity, availability, strength, geometry, positioning accuracy and reliability based on a number of scenarios. The design, structure and major components of the simulator are outlined. Useful time-stamped spatial patterns of the signal performance over the experimental urban area have been revealed which are valuable for supporting location based services applications, such as emergency responses, the optimization of wireless communication infrastructures and vehicle navigation services.

• 센서학회지
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• 제16권2호
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• pp.110-114
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• 2007

In this paper we present 3-D Navigation View, a three-dimensional visualization of indoor environment which serves as an intuitive and unified user interface for our developed indoor location tracking system via Virtual Reality Modeling Language (VRML) in web environment. The extracted user's spatial information from indoor location tracking system was further processed to facilitate the location indication in virtual 3-D indoor environment based on his location in physical world. External Authoring Interface (EAI) provided by VRML enables the integration of interactive 3-D graphics into web and direct communication with the encapsulated Java applet to update position and viewpoint of user periodically in 3-D indoor environment. As any web browser with VRML viewer plug-in is able to run the platform independent 3-D Navigation View, specialized and expensive hardware or software can be disregarded.

• 한국HCI학회:학술대회논문집
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• 한국HCI학회 2006년도 학술대회 2부
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• pp.633-638
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• 2006

We investigated the importance and efficiency of active and passive exploration on the recognition of objects in a variety of virtual environments (VEs). In this study, 54 participants (19 males and 35 females) were randomly allocated into one of two navigation conditions (active and passive navigation). The 3D visual display was presented through HMD and participants used joysticks to navigate VEs. The VEs consisted of exploring four rooms (library, office, lounge, and conference room), each of which had 15 objects. 'Active navigation' was performed by allowing participants to self-pace and control their own navigation within a predetermined time limitation for each room. 'Passive navigation' was conducted by forced navigation of the four rooms in random order. Total navigation duration and objects for both navigations were identical. After navigating VEs, participants were asked to recognize the objects that had been in the four rooms. Recognition for objects was measured by response time and the percentage of correct, false, hit, and miss responses. Those in the active navigation condition had a significantly higher percentage of hit responses (t (52) = 4.000 p < 0.01), and a significantly lower percentage of miss responses (t (52) = -3.763, p < 0.01) in object recognition than those in the passive condition. These results suggest that active navigation plays an important role in spatial cognition as well as providing a better explanation about the efficiency of learning in a 3D-based program.