• Journal of IKEEE
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• v.23 no.1
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• pp.181-187
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• 2019

In this paper, we demonstrated a power amplifier monolithic microwave integrated circuit (MMIC) for X-band radar applications. It utilizes commercial $0.25{\mu}m$ GaN-based high electron mobility transistor (HEMT) technology and delivers more than 20 W of output power. The developed GaN-based power amplifier MMIC has small signal gain of over 22 dB and saturated output power of over 43.3 dBm (21.38 W) in a pulse operation mode with pulse width of $200{\mu}s$ and duty cycle of 4% over the entire band of 9 to 10 GHz. The chip dimensions are $3.5mm{\times}2.3mm$, generating the output power density of $2.71W/mm^2$. Its power added efficiency (PAE) is 42.6-50.7% in the frequency bandwidth from 9 to 10 GHz. The developed GaN-based power amplifier MMIC is expected to be applied in a variety of X-band radar applications.

• Journal of Ocean Engineering and Technology
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• v.30 no.3
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• pp.227-233
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• 2016

This paper presents an underwater structure 3D reconstruction method using a 2D multibeam imaging sonar. Compared with other underwater environmental recognition sensors, the 2D multibeam imaging sonar offers high resolution images in water with a high turbidity level by showing the reflection intensity data in real-time. With such advantages, almost all underwater applications, including ROVs, have applied this 2D multibeam imaging sonar. However, the elevation data are missing in sonar images, which causes difficulties with correctly understanding the underwater topography. To solve this problem, this paper concentrates on the physical relationship between the sonar image and the scene topography to find the elevation information. First, the modeling of the sonar reflection intensity data is studied using the distances and angles of the sonar beams and underwater objects. Second, the elevation data are determined based on parameters like the reflection intensity and shadow length. Then, the elevation information is applied to the 3D underwater reconstruction. This paper evaluates the presented real-time 3D reconstruction method using real underwater environments. Experimental results are shown to appraise the performance of the method. Additionally, with the utilization of ROVs, the contour and texture image mapping results from the obtained 3D reconstruction results are presented as applications.

• Journal of the Korea Computer Industry Society
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• v.8 no.2
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• pp.131-140
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• 2007

The rapidly expanding field of animation is constantly looking for skilled animators in both 2D and 3D applications. The animation industry, as little as 10 years ago, was limited to the occasional blockbuster release. Today, we find animation everywhere, from medical applications to architecture to feature films and gaming, Especially, 3D games have become a way of life, but it still requires a lot of effort, on the programming side, to get it looking respectable. Programmers take a much more charge of part than designersin the real life game production. In this paper, I would analyze how to easily create 3D game animation using Virtools even if you are a non-programmer.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.16 no.1
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• pp.169-175
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• 2016

Geofence is a virtual perimeter for a real-world geographical area, which could be statically or dynamically established the specified area if necessary. Many geofencing applications incorporate 2D(two-dimensional) map such as the Google map, allowing administrators to define boundaries on top of a satellite view of a specific geographical area. But these applications do not provide 3D(three-dimensional) spatial information as well as 2D location information no matter where indoor or outdoor. Therefore we propose a mechanism to identify indoor or outdoor location for 3D geofence, and implement 3D geofence using smartphone. The proposed mechanism identifies the position information on 3D geofence regardless of indoor or outdoor, inter-floor with only GPS and WiFi. In the near future, 3D geofence as well as LBS are promising applications that become possible when IoT can become organized and connected by location.

• Applied Microscopy
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• v.46 no.2
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• pp.71-75
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• 2016

The scanning electron microscope (SEM) offers two-dimensional (2D) micrographs of three-dimensional (3D) objects due to its inherent operating mechanisms. To overcome this limitation, other devices have been used for quantitative morphological analysis. Many efforts have been made on the applications of software-based approaches to 3D reconstruction and measurements by SEM. Based on the acquisition of two stereo images, a multi-view technique consists of two parts: (i) geometric calibration and (ii) image matching. Quantitative morphological parameters such as height and depth could be nondestructively measured by SEM combined with special software programs. It is also possible to obtain conventional surface parameters such as roughness and volume of biomedical specimens through 3D SEM surface reconstruction. There is growing evidence that conventional 2D SEM without special electron detectors can be transformed to 3D SEM for quantitative measurements in biomedical research.

• Journal of the Korea Computer Graphics Society
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• v.2 no.1
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• pp.61-67
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• 1996

3D graphics applications require managing and displaying objects as well as handling events. These tasks are quite complex for applications to worry about and are common to many applications. Therefore, many attempts have been made to provide toolkits with these capabilities for those applications. This paper presents a toolkit that is easy to use and well suited for the modeling and rendering tasks. The object-oriented programming techniques used in designing the toolkit make it flexible and easily extensible.

• Journal of the Korean Society for Precision Engineering
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• v.23 no.5 s.182
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• pp.143-148
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• 2006

It is still very difficult to generate a geometry model and finite element model, which has complex and many free surface, even though 3D CAD solutions are applied. Furthermore, in the medical field, which is a big growth area of recent years, there is no drawing. For these reasons, making a geometry model, which is used in finite element analysis, is very difficult. To resolve these problems and satisfy the requests of the need to create a 3D digital file for an object where none had existed before, new technologies are appeared recently. Among the recent technologies, there is a growing interest in the availability of fast, affordable optical range laser scanning. The development of 3D laser scan technology to obtain 3D point cloud data, made it possible to generate 3D model of complex object. To generate CAD and finite element model using point cloud data from 3D scanning, surface reconstruction applications have widely used. In the early stage, these applications have many difficulties, such as data handling, model creation time and so on. Recently developed point-based surface generation applications partly resolve these difficulties. However there are still many problems. In case of large and complex object scanning, generation of CAD and finite element model has a significant amount of working time and effort. Hence, we concerned developing a good direct finite element model generation method using point cloud's location coordinate value to save working time and obtain accurate finite element model.

• 한국정보컨버전스학회:학술대회논문집
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• 2008.06a
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• pp.125-128
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• 2008

The aim this master thesis is to find out if is possible to Integrate haptic hardware support in the source 3D game engine Crystal Space. Integrating haptic support would make it possible to get a haptic representation of 3D geometry in Crystal Space and therefore take advantage of all the benefits a 3D game engine provides, when building haptic applications, An implementation of the support should be as low-cost as Possible by taking advantage of available source haptic API alternatives. The thesis report presents an evaluation of available haptic APIs and comes up with a design and an implementation. The solution has been implemented as a Crystal Space plugin by using modified parts of the e-Touch open module API. The plugin makes it possible to utilize the Phantom haptic device to touch and feel the 3D environments in a Crystal Space application. Two demo applications have also been constructed to show the capabilities of the plugin.

• Proceedings of the Korea Society of Information Technology Applications Conference
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• 2001.11a
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• pp.207-208
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• 2001

• Journal of the HCI Society of Korea
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• v.2 no.2
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• pp.53-59
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• 2007

Several researches in 3D interaction have identified and extensively studied the four basic interaction tasks for 3D/VE applications, namely, navigation, selection, manipulation and system control. These interaction schemes in the real world or VE are generally suitable for interacting with small graspable objects. In some applications, it is important to duplicate real world behavior. For example, a training system for a manual assembly task and usability verification system benefits from a realistic system for object grasping and manipulation. However, it is not appropriate to instantly apply these interaction technologies to such applications, because the quality of simulated grasping and manipulation has been limited. Therefore, we introduce the intuitive and natural 3D interaction haptic interface supporting high-precision hand operations and realistic haptic feedback.