• Proceedings of the Korean Society of Precision Engineering Conference
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• 2007.11a
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• pp.79-80
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• 2007

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2013.05a
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• pp.195-196
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• 2013

• Journal of Biomedical Engineering Research
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• v.3 no.2
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• pp.119-122
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• 1982

This paper presents the principles of image formation in NMR(Nuclear Magnetic Resonance) tomography. NMR tomographic imaging is a newly emerging, noninvasive, three-dimensional imaging technique. This new technique is an interdisciplinary science which encompasses the latest technologies in electrical, electronics, computers, physics, chemistry, mathematics, and medical sciences.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2009.06a
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• pp.937-938
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• 2009

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2008.06a
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• pp.737-738
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• 2008

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2012.04a
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• pp.320-321
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• 2012

• Spatial Information Research
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• v.13 no.4 s.35
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• pp.373-380
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• 2005

Mobile Mapping Systems are effective systems to acquire the position and image data using vehicle equipped with the GPS (Global Positioning System), IMU (Inertial Measurement Unit), and CCD camera. They are used in various fields of road facility management, map update, and etc. In the general photogrammetry such as aerial photogrammetry, GCP (Ground Control Point)s are needed to compute the image exterior orientation elements (the position and attitude of camera). These points are measured by field survey at the time of data acquisition. But it costs much time and money. Moreover, it is not possible to make sufficient GCP as much as we want. However Mobile Mapping Systems are more efficient both in time and money because they can obtain the position and attitude of camera at the time of photographing. That is, Image Orientation Technique must use GCP to compute the image exterior orientation elements, but on the other hand Direct Georeferencing can directly compute the image exterior orientation elements by GPS/INS. In this paper, we analyze about the positional accuracy comparison of ground point using the Image Orientation Technique and Direct Georeferencing Technique.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.24 no.6
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• pp.759-767
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• 2020

This paper proposes a new Recurrent neural network (RNN) based spectrum sensing technique for cognitive radio communications. The proposed technique determines the existence of primary user's signal without any prior information of the primary users. The method performs high-speed sampling by considering the whole sensing bandwidth and then converts the signal into frequency spectrum via fast Fourier transform (FFT). This spectrum signal is cut in sensing channel bandwidth and entered into the RNN to determine the channel vacancy. The performance of the proposed technique is verified through computer simulations. According to the results, the proposed one is superior to more than 2 [dB] than the existing threshold-based technique and has similar performance to that of the existing Convolutional neural network (CNN) based method. In addition, experiments are carried out in indoor environments and the results show that the proposed technique performs more than 4 [dB] better than both the conventional threshold-based and the CNN based methods.

• Nuclear Engineering and Technology
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• v.53 no.8
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• pp.2600-2609
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• 2021

Low cycle fatigue behaviors of SA508-3 low-alloy steel were investigated in room-temperature air, high-temperature air and in light water reactor (LWR) water environments. The fatigue mean curve and design curve for the low-alloy steel are developed based on the fatigue data in room-temperature and high-temperature air. The environmental fatigue model for low-alloy steel is developed by the environmental fatigue correction factor (F_en) methodology based on the fatigue data in LWR water environments with the consideration of effects of strain rate, temperature, and dissolved oxygen concentration on the fatigue life.

• Journal of Aerospace System Engineering
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• v.18 no.5
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• pp.81-89
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• 2024

Recently, both volumes and weights of antennas are increasing because of advancement of satellite missions. Research studies on mesh deployable antennas that can be highly stowable and lightweight are also increasing. When a deployable mesh antenna is subjected to repeated deployment tests on the ground, vibration of launch environments can cause slip between the antenna structure and the mesh fabric, resulting in failure to maintain the surface curvature of the antenna and Openning Per Inch (OPI). Such failure is the main cause of RF performance and mission capability degradation. Thus, studying a fastening technique to prevent slip between the antenna structure and mesh fabric is essential. This study proposed a Clamping fastening technique using rivets between the antenna structure and the mesh fabric. To evaluate the fastening efficiency of the Clamping fastening technique, tensile tests were conducted according to antenna structure type and rivet increment. Results were analyzed and fastening efficiency of the proposed clamping fastening technique was verified.