• ETRI Journal
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• v.33 no.2
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• pp.291-294
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• 2011

This letter proposes an open-ended waveguide antenna with a single split-ring resonator. In contrast to the waveguide antennas incorporating multiple rings reported in a previous study, which exhibited narrow bandwidth, the proposed antenna uses only one ring to achieve broader bandwidth while keeping the aperture small. A single ring has a relatively low quality factor compared to multiple rings. The simulated and measured fractional bandwidth was 4.13% and 4.03%, respectively, which is much broader than the fractional bandwidth of about 1% demonstrated in a previous study. This simple technique can be used in many applications that require small apertures including near-field probes and array elements.

• Journal of the Optical Society of Korea
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• v.14 no.1
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• pp.28-32
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• 2010

We demonstrate binary spectral phase coded waveform discrimination at 10 GHz for narrow band optical code-division multiple-access (NB-OCDMA) via direct electrical detection without using any optical hard-limiter. Only 9 phase-locked, 10 GHz spaced, spectral lines within a 100 GHz spectral window are used for the phase coding. Considerably high contrast ratio of 5 between signal and multiuser access interference noise can be achieved for $4{\times}10\;G\;pulse/sec$ timing coordinated OCDMA at a simple electrical receiver with 50 GHz bandwidth.

• Proceedings of the Korea Information Processing Society Conference
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• 2012.11a
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• pp.552-555
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• 2012

The main goal of this paper is to develop a robust visual tracking algorithm with particle filtering. Visual Tracking with particle filter technique is not easy task due to cluttered environment, illumination changes. To deal with these problems, we develop an efficient observation model for target tracking with particle filter. We develop a robust phase correlation combined with motion information based observation model for particle filter framework. Phase correlation provides straight-forward estimation of rigid translational motion between two images, which is based on the well-known Fourier shift property. Phase correlation has the advantage that it is not affected by any intensity or contrast differences between two images. On the other hand, motion cue is also very well known technique and widely used due to its simplicity. Therefore, we apply the phase correlation integrated with motion information in particle filter framework for robust tracking. In experimental results, we show that tracking with multiple cues based model provides more reliable performance than single cue.

• Fisheries and Aquatic Sciences
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• v.27 no.4
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• pp.225-230
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• 2024

We examined the dB difference in target strength at multiple frequencies (ΔTS) for the identification of Antarctic krill (Euphausia superba) and ice krill (Euphausia crystallorophias) using a stochastic distorted-wave Born approximation model. Our investigation focused on ΔTS patterns at multiple frequencies in relation to size, along with key acoustic properties influencing TS, including density and sound speed contrast, fatness, and orientation. The findings revealed that the orientation and fatness significantly affect the ΔTS patterns. The results provide insight into the importance of the multi-frequency technique for estimating krill biomass and their ecological interactions with environmental features in the Southern Ocean.

• Journal of Yeungnam Medical Science
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• v.30 no.2
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• pp.105-108
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• 2013

Type 1 neurofibromatosis (von Recklinghausen's disease, NF-1) is an autosomal-dominant neurocutaneous-disorder characterized by systemic cafe'-au-lait spots, multiple cutaneous neurofibromas, axillary or inguinal freckling, and Lisch nodules (pigmented iris hamartomas). Approximately 10-25% of NF1 patients have gastrointestinal neoplasms. Gastrointestinal stromal tumor (GIST) in patients with neurofibromatosis is most commonly found in the small bowel and the stomach, and approximately 60% of such patients have multiple tumors or multiple tumor sites. Although, the increased incidence of GIST in patients with neurofibromatosis is well documented in pathology literature in English, but has rarely been documented in Korea. Here, we report a case of multiple GISTs in a 48-year-old woman accompanied by NF1. She was admitted to Yeung-nam University Hospital with complaints of melena and dyspnea. A contrast-enhanced computed tomography (CT) scan revealed that multiple soft tissue masses were occupying the entire peritoneal cavity. An ultrasonogram- guided biopsy was performed and the tumors were found to have been composed of tumor cells that were positive for c-kit protein. The patient was put on Imatinib mesylate treatment, and further follow-up will be carried out.

• Journal of Korea Multimedia Society
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• v.22 no.12
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• pp.1376-1384
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• 2019

The cosmetic and behavioral aspects of aging have become increasingly evident over the years. Physical aging in people can easily be observed on their face, posture, voice, and gait. In contrast, bone aging only becomes apparent once significant bone degeneration manifests through degenerative bone diseases. Therefore, a more accurate and timely assessment of bone aging is needed so that the determinants and its mechanisms can be more effectively identified and ultimately optimized. This study proposed a deep learning approach to assess the bone age of an adult using whole-body bone scintigraphy. The proposed approach uses multiple inputs deep neural network architectures using a loss function, called mean-variance loss. The data set was collected from Chonnam National University Hwasun Hospital. The experiment results show the effectiveness of the proposed method with a mean absolute error of 3.40 years.

• Wind and Structures
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• v.19 no.6
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• pp.585-601
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• 2014

The effect of multiple roughness changes close to a building site was examined through three dimensional computational fluid dynamics (CFD) simulations conducted in a virtual boundary layer wind tunnel (V-BLWT). The results obtained were compared with existing wind speed models, namely ESDU-82026 and Wang and Stathopoulos (WS) model. The latter was verified by wind tunnel tests of sixty nine cases of multiple roughness patches, and also with a simplified 2D numerical model. This work extends that numerical study to three dimensions and also models roughness elements explicitly. The current numerical study shows better agreement with the WS model, that has shown better agreements with BLWT tests, than the ESDU model. This is in contrast to previous results of Wang and Stathopoulos, who concluded that CFD shows better agreement with the ESDU model. Many cases were simulated in a V-BLWT that has same dimensions as BLWT used in the original experiment and also in a reduced symmetrical version (S-BLWT) that takes advantage of regular arrangement of roughness blocks. The S-BLWT gives results almost identical to V-BLWT simulations, while achieving significant reduction on computational time and resources.

• Journal of the Korean earth science society
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• v.36 no.5
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• pp.437-446
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• 2015

Many edge detection methods, based on horizontal and vertical derivatives, have been introduced to provide us with intuitive information about the horizontal distribution of a subsurface anomalous body. Understanding the characteristics of each edge detection method is important for selecting an optimized method. In order to compare the characteristics of the individual methods, this study applied each method to synthetic magnetic data created using homogeneous prisms with different sizes, the numbers of bodies, and spacings between them. Seven edge detection methods were comprehensively and quantitatively analyzed: the total horizontal derivative (HD), the vertical derivative (VD), the 3D analytic signal (AS), the title derivative (TD), the theta map (TM), the horizontal derivative of tilt angle (HTD), and the normalized total horizontal derivative (NHD). HD and VD showed average good performance for a single-body model, but failed to detect multiple bodies. AS traced the edge for a single-body model comparatively well, but it was unable to detect an angulated corner and multiple bodies at the same time. TD and TM performed well in delineating the edges of shallower and larger bodies, but they showed relatively poor performance for deeper and smaller bodies. In contrast, they had a significant advantage in detecting the edges of multiple bodies. HTD showed poor performance in tracing close bodies since it was sensitive to an interference effect. NHD showed great performance under an appropriate window.

• The Journal of Korean Physical Therapy
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• v.27 no.1
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• pp.61-67
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• 2015

Purpose: This study was conducted in order to investigate the effectiveness of an 8-week virtual reality exercise program designed around the Nintendo Wii (Wii), in improving balance among patients with Multiple Sclerosis (MS). Methods: The study included 16 patients with MS (10 female, 6 male) who were assigned randomly to experimental (n=8) or control group (n=8). Experimental group performed three 40-minute Wii balance-training sessions per week, for 8 weeks. The control group did not perform any of the training programs. A computerized dynamic posturography (Sensory Organizing Test, SOT) was used to evaluate all patients at baseline and at the end of the treatment protocol. Statistical significance was tested in between the patients before and after treatment by t-test. Results: After 24 training sessions, SOT showed significant difference on condition 5, 6, and vestibular ratios within the experimental group from baseline to post-intervention. By contrast, no significant difference was observed within the control groups. Conclusion: These findings demonstrated that the virtual reality training program could improve the outcomes in terms of balance in the MS population. Long term follow ups and the development of more efficient virtual reality training programs are needed.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.05a
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• pp.745-746
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• 2013

TWDM PON (time and wavelength division multiplexed passive optical network) uses multiple wavelengths to transmit packets upstream and downstream. In upstream transmission, if we use only one wavelength, the unused bandwidth is equally distributed to each ONU (optical network unit). In contrast, when multiple wavelengths are used, the unused remainders of wavelengths are different from each other. Therefore, it is difficult to fairly allocate the unused bandwidth to each ONU. This paper proposes a new method to allocate the unused bandwidth to each ONU in TWDM PON which uses multiple wavelengths.