• Journal of the Korean Institute of Telematics and Electronics D
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• v.36D no.7
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• pp.26-33
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• 1999

In order to examine the effect of beam location n the performance of bridge type piozoresistive silicon accelerometer, three sensors having different location of beams were simulated by FEN(finite element method) and fabricated by RIE(reactive ion etching) and KOH etching method using SDB(silicon direct bonding) wafer, Results of the FEM simulation present that the 1st resonace frequency and Z axis sensitivity of each sensor are identical but the 2nd, and the 3rd resonace frequency and X, Y axis sensitivity are different. Even though the 1st resonance frequency and Z axis sensitivity measured from fabricated sensors do not perfectly coincide with each other, all 3 type sensors present 180 ~ 220N/G of Z sensitivity at 5 V supply voltage and 1.3 ~ 1.7kHz of the 1st resonance frequency and about 2% of lateral sensitivity.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.7 no.6
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• pp.1244-1251
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• 2003

In the paper, we develop the ‘Navigation Mechanism’ that can present the 3D space and trace the location in the user's viewpoint. Especially, using this mechanism, VRML tools are used to develop the virtual reality space in the internet. These mechanism can effectively represent the 3D virtual reality space and apply the many 3D related parts like architefure, education, entertainment and so on.

• The Journal of the Acoustical Society of Korea
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• v.35 no.1
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• pp.35-41
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• 2016

Based on correlation and least square method, a closed-form algorithm for estimating the location of mixed far-field and near-field source is presented using the Uniform Circular Array (UCA). Recently, for a homogeneous circular arrangement case, a correlation based closed-form algorithm is proposed to estimate 2-D angle (azimuth, elevation) and the extended algorithm is proposed to 3-D location (azimuth, elevation, range). These algorithms assume the far-field source or near-field source only. Therefore, for mixed source localization, the proposed algorithm estimates source location with the assumption of far-field source, and then estimates the range to distinguish the far-field from the near-field source. For both cases, numerical experiments have been performed, which confirmed the validity of the proposed algorithm.

• Journal of the Ergonomics Society of Korea
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• v.29 no.6
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• pp.861-868
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• 2010

This study explored an extended three-dimensional Fitts' law that is more suited for the pointing task than the conventional Fitts' law. The experiments were conducted under the manipulation of the distance to the target, size of the target, and direction of the target's location that can be described by two angles, $\theta1$ and $\theta2$. Considering the starting point as the center of coordinates, $\theta1$ is the angle between the positive z-axis and the target location and $\theta2$ is the angle between the positive y-axis and the projected target location on the x-y plane. From the experimental results, we confirmed that all four variables significantly affect the movement time. As we extended the index of difficulty of the conventional Fitts' model by incorporating $\theta1$ and $\theta2$, we established an extended Fitts' model that showed better accordance with the empirical data than the conventional Fitts' model and 3D Fitts' law of Murata and Iwase, in terms of the $r^2$ and the standard error of the residual between the measured movement time and the predicted value.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2022.04a
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• pp.245-246
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• 2022

Recently, research on the self-healing of concrete using bacteria has been actively conducted. The self-healing method using bacteria has a low self-healing rate and the surrounding environment of the fracture site is very important. A previous study to solve this problem involves the manufacture of capsules using 3D printing. Fracture position control was an important topic in 3D printing-based capsules. In this study, to compensate for the shortcomings of existing studies, a capsule capable of selective destruction location control was produced using PDMS-based molds that are not restricted by the environment. Resin capsules were prepared for each part using several molds and a bonding surface was arranged. In order to verify this on the bonding surface, fracture strength and wave unit values were analyzed through a three-way compression experiment. It can be seen that as the curing time increases, the deviation between samples decreases. In addition, through experiments, it was confirmed that the junction surface and wave unit values coincide in all three directions. It can be used for self-healing research using various solutions.

• The KIPS Transactions:PartA
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• v.14A no.4
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• pp.209-214
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• 2007

In conventional game systems, virtual environments usually have just the role of a background without the direct relationships for game characters. nev do not consider the semantics about virtual environments. In this paper, we develop a game navigation system that provides semantic information about virtual environments including geographical, historical or my other location-dependent information. Then, the game character obtains the geographical location and its related information when it navigates through a virtual environment. It can be an implementation method for a semantic virtual environment because it can have the environment maintain its semantics depending on the specific location. In addition, we describe a method that can control a character's motion in the semantic virtual environment interactively, and that can input specific information according to the location of the character.

• Journal of the Korea institute for structural maintenance and inspection
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• v.27 no.5
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• pp.49-56
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• 2023

This study proposed a damage location estimation method for automated image-based port infrastructure inspection. Memory efficiency was improved by calculating the homography matrix using feature detection technology and outlier removal technology, without going through the 3D modeling process and storing only damage information. To develop an algorithm specialized for port infrastructure, the algorithm was optimized through ground-truth coordinate pairs created using images of port infrastructure. The location errors obtained by applying this to the sample and concrete wall were (X: 6.5cm, Y: 1.3cm) and (X: 12.7cm, Y: 6.4cm), respectively. In addition, by applying the algorithm to the concrete wall and displaying it in the form of an exterior damage map, the possibility of field application was demonstrated.

• The Bulletin of The Korean Astronomical Society
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• v.40 no.1
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• pp.64.2-64.2
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• 2015

We present a comprehensive catalog of 307 front-side halo (partial and full) CMEs during 2009 and 2013 observed by both SOHO and STEREO. This catalog includes 2D CME properties from single spacecraft (SOHO) as well as 3D ones from multi-spacecraft. To determine the 3D CME properties (speed, angular width, and source location), we use the STEREO CME analysis tool based on a triangulation method. In this paper, we compare between 2D and 3D CME properties, which is the first statistical comparison between them. As a result, we find that 2D speeds tend to be about 20% underestimated when compared to 3D ones. The 3D angular width ranges from $15^{\circ}$ to $109^{\circ}$, which are much smaller than the 2D angular widths with the mean value of $225^{\circ}$. We also find that a ratio between 2D and 3D angular width decreases with central meridian distance. The 3D source locations from the triangulation method are similar to the flare locations. The angular width-speed relationship in 3D is much stronger than that in 2D.

• Journal of Digital Contents Society
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• v.19 no.2
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• pp.237-243
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• 2018

Most of public underground facilities are installed under the ground, thus it is difficult to recognize the accurate location even with the drawings. Studies are conducted to understand exact position of underground facilities using augmented reality. However, in those studies, establishing of additional 3D object model database is needed when AR system is used at field. Because most of public underground facility information are established as 2 dimensional. In this study, AR system is developed as mobile application which can use original 2D underground facility data to transfer 3D AR data automatically without additional 3D database establishment.

• Ecology and Resilient Infrastructure
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• v.7 no.3
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• pp.171-180
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• 2020

With the increase in industrialization and urbanization, scarcity of space for leisure life has become an important issue. Opportunities such as natural scenery and ecological experiences provided by waterfront spaces around streams are fundamental factors in the development of the community and creation of a hydrophilic park. In the past, on-site surveys have been conducted using human resources to quantify the number of river visitors, but the accuracy of the results was not sufficient owing to limitations in expenses, manpower, space, and time. In this study, to overcome this problem, we estimated the number of visitors using the location information related to hydrophilic parks. The study areas were Samrak Ecological Park and Daejeo Ecological Park located downstream of the Nakdong River. We compared and analyzed the pattern of the visitors by using the large communication data and the visiting pattern based on GPS location information. The GPS location information is based on Google Popular Times and Kakao visitor data. When the GPS location data were used, the pattern for weekday and weekend visitors was clearer than when the large communication data were used. Therefore, it is expected to be similar to the result of GPS location information if the number of visitors is extracted under the condition of precision of pCELL size and residence time of 30 minutes or more when using future communication big data. In addition, if revisions such as the Personal Information Protection Act are made to extract more accurate data, by estimating the number of visitors based on GPS data, more accurate indicators of the number of visitors can be derived.