• Investigative Magnetic Resonance Imaging
• /
• v.22 no.1
• /
• pp.71-77
• /
• 2018

Purpose: To develop a two-dimensional (2D) image-based respiratory motion correction technique for free-breathing coronary magnetic resonance angiography (MRA). Materials and Methods: The proposed respiratory navigator obtained aliased a 2D sagittal image from under-sampled k-space data and utilized motion correlation between the aliased images. The proposed navigator was incorporated into the conventional coronary MRA sequence including the diaphragm navigator and tested in three healthy subjects. Results: The delineation of major coronary arteries was significantly improved using the proposed 2D motion correction (S/I and A/P) compared to one-dimensional (S/I) correction using the conventional diaphragm navigator. Conclusion: The 2D image-based respiratory navigator was proposed for free-breathing coronary angiography and showed the potential for improving respiratory motion correction compared to the conventional 1D correction.

• Investigative Magnetic Resonance Imaging
• /
• v.22 no.4
• /
• pp.209-217
• /
• 2018

Purpose: The objective of this study was to obtain improved susceptibility weighted images (SWI) of the cervical spinal cord using respiratory-induced artifact compensation. Materials and Methods: The artifact from $B_0$ fluctuations by respiration could be compensated using a double navigator echo approach. The two navigators were inserted in an SWI sequence before and after the image readouts. The $B_0$ fluctuation was measured by each navigator echoes, and the inverse of the fluctuation was applied to eliminate the artifact from fluctuation. The degree of compensation was quantified using a quality index (QI) term for compensated imaging using each navigator. Also, the effect of compensation was analyzed according to the position of the spinal cord using QI values. Results: Compensation using navigator echo gave the improved visualization of SWI in cervical spinal cord compared to non-compensated images. Before compensation, images were influenced by artificial noise from motion in both the superior (QI = 0.031) and inferior (QI = 0.043) regions. In most parts of the superior regions, the second navigator resulted in better quality (QI = 0.024, P < 0.01) compared to the first navigator, but in the inferior regions the first navigator showed better quality (QI = 0.033, P < 0.01) after correction. Conclusion: Motion compensation using a double navigator method can increase the improvement of the SWI in the cervical spinal cord. The proposed method makes SWI a useful tool for the diagnosis of spinal cord injury by reducing respiratory-induced artifact.

• Journal of the Institute of Electronics Engineers of Korea CI
• /
• v.45 no.3
• /
• pp.58-67
• /
• 2008

In this paper, we first point out difficulties faced by CG artists in the shading process: (1) a lot of technical details on shaders required, (2) long rendering time, and (3) repeated trials-and-errors. To make them overcome such difficulties, we propose Shader Space Navigator, a system that efficiently searches for shaders similar to a given query shader from a shader database containing a large number of quality shaders. With Shader Space Navigator, CG artists find appropriate shaders from the database that are very close to the final result shader, and thus complete the shading process easily by slightly tuning some attributes of those shaders. Thus, the CG artists can create their final shaders in an intuitive and efficient way without a large number of time-consuming rendering processes. Also, we deal with implementation issues related to Shader Space Navigator and constructing an abundant shader database in detail.

• Proceedings of the Korea Information Processing Society Conference
• /
• 2009.04a
• /
• pp.122-125
• /
• 2009

기존의 인터넷 익스플로러는 높은 보급률의 이점을 지니고 있지만 인터넷을 이용하기 위한 기본지식의 필요성과 키보드, 마우스와 같은 장치를 이용한 입력방식은 장애인 및 고령층의 사용자들이 이용하기에는 불편하다. 이와 같은 문제점을 해결하고자 본 논문에서는 웹 서비스 기술을 이용하여 기존의 음성인식 시스템을 웹 서비스로 재구성하고 클라이언트가 음성인식 웹 서비스를 요청하고 음성명령이 가능하도록 인터넷 익스플로러에 음성명령이 가능한 Navigaotr를 Toolbar 형태의 프로그램을 구현하였다. 본 시스템은 클라이언트가 사용하는 음성 Navigator Toolbar와 웹 서비스를 통해서 음성 서비스를 제공하는 음성 서비스 프로바이더로 구성된다. 음성 Navigator Toolbar는 인터넷 환경에서 음성데이터를 바이너리 포맷형식인 DIME을 이용하여 음성 서비스 프로바이더로 전송하고 반환 결과를 가지고 URL Navigator를 통해 인터넷 페이지를 이동시킨다. 음성 서비스 프로바이더는 사용자가 전송한 음성데이터를 인식기를 통해 인식하고 결과를 가지고 정보 Database를 검색하여 실제 인터넷 주소를 사용자에게 반환한다.

• Proceedings of the Korea Society of Design Studies Conference
• /
• 2003.05a
• /
• pp.240-241
• /
• 2003

• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• 2023.05a
• /
• pp.194-195
• /
• 2023

Recently, Maritime Autonomous Surface Ship(MASS) technology has attracted attention as a key technology for ship safety, efficiency, and economic feasibility in the marine field. Decision-making by the navigator's Situation Awareness (SA) for remote control on shore is expected to play an important role in ship collision avoidance. In this study, the navigator's decision-making time for the collision situation was measured.

• International Journal of Fuzzy Logic and Intelligent Systems
• /
• v.14 no.2
• /
• pp.130-135
• /
• 2014

For the past three decades, ship-to-ship collision accidents have steadily increased on the coast of South Korea by about 20% annually. Marine accidents have become more likely and more devastating in areas with increasing marine traffic and rising numbers of high-speed ships. Over 30% of the marine accidents in South Korea are concentrated in spring, since Korea's coast is often covered in dense fog at this time of the year. Fog is generated when a large temperature range exists within a day, and this daily temperature range has increased due to abnormal weather conditions. This research proposed a system for transmitting a navigator's intention utilizing electronic methods. A navigator's intention was expressed on the electronic navigation chart for easier understanding of the surrounding situation, and the effectiveness of the system was verified through practical tests.

• Proceedings of the KOSOMBE Conference
• /
• v.1998 no.11
• /
• pp.315-316
• /
• 1998

The purpose of this study is a potentiality examination of an infrared camera system for the 3D navigator which can be used in the field of neurosurgery. Nowadays, CAS(computer aided surgery) technique using 3D navigator is rapidly spread into the neurosurgeric operation such as brain and spine surgery. Several techniques which can detect 3D position of a probe have been proposed. These include mechnical arm, magnetic field, optical and ultrasonic sensing methods. In this study, we decided that using optical sensing method and tested a conventional CCD camera with a infrared filter and LEDs. Pulnix TM-300 camra has sufficient spectral response in the range of near infrared. Acquired image of infrared LEDs also sufficient quality.

• Journal of Navigation and Port Research
• /
• v.33 no.7
• /
• pp.463-467
• /
• 2009

In near future, more congested and dangerous marine traffic environment due to the rapid marine traffics increase and ship handling difficulty by enlargement of ship size is predicted. In this paper, an navigation supporting system proposal made to enhance the safe navigation by providing the collision avoidance informations to the navigator via marine traffic environment assessment. Proposed navigation supporting system displays results of marine traffic environment assessment, degree of the dangers and gives reason of danger which is enhance situational awareness of navigator. For this purpose, results of marine traffic environment assessment which is obtained via real time assessment sent to the designated server and through the connection with navigation supporting system navigator being enable to see all those informations on the computer screen Navigator would utilize those information to make a decision in the difficult waterways and thus safe navigation could be enhanced.

• Journal of Korean Society of Transportation
• /
• v.26 no.3
• /
• pp.129-141
• /
• 2008

Portable navigation markets grew up to 95% last year. This study aims to develop a business model for pedestrian-oriented portable navigator for street shoppers. Related previous studies developed successfully the alogrithm for a portable navigator, and the current study seeks for diverse ways to turn this system into a new type of on & off line-based LBS business. The business model proposed in this study adopted two different approaches of benefit yields based on the structural analysis of so-called Wanavi navigation system. One is segmented approach seeking for benefits from each individual system component such as communication network, contents, and platform. The other approach is to run the business by integrating relevant system componts in every possible way to attract customers to this portable navigator. The purpose of this proposal is not limited to activate emerging walking navigator markets, but to aim at creating idealistic free market system where all the shoppers are furnished complete market information to the fullest extent when they go on shopping.