• The Journal of Korean Institute of Communications and Information Sciences
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• v.38C no.9
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• pp.740-745
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• 2013

This paper presents BER, FER performance comparison, especially on PHY mode of IEEE 802.15.4g and IEEE 802.11 under AWGN channel through a simulation, which is communication method using identical frequency bandwidth in M2M environment. This considers suitable communication method of required parameter. It is advantageous that FSK method is used in situations where the system require low complexity and inexpensive structure. And OFDM method is considered for system performance. Further, when the high throughput and various traffic characteristics of the system are required, it can be considered that the method of IEEE 802.11 OFDM PHY mode is used.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2007.11a
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• pp.330.2-330.2
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• 2007

• Imaging Science in Dentistry
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• v.52 no.4
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• pp.393-398
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• 2022

Purpose: This study proposed a generative adversarial network (GAN) model for T2-weighted image (WI) synthesis from proton density (PD)-WI in a temporomandibular joint(TMJ) magnetic resonance imaging (MRI) protocol. Materials and Methods: From January to November 2019, MRI scans for TMJ were reviewed and 308 imaging sets were collected. For training, 277 pairs of PD- and T2-WI sagittal TMJ images were used. Transfer learning of the pix2pix GAN model was utilized to generate T2-WI from PD-WI. Model performance was evaluated with the structural similarity index map (SSIM) and peak signal-to-noise ratio (PSNR) indices for 31 predicted T2-WI (pT2). The disc position was clinically diagnosed as anterior disc displacement with or without reduction, and joint effusion as present or absent. The true T2-WI-based diagnosis was regarded as the gold standard, to which pT2-based diagnoses were compared using Cohen's ĸ coefficient. Results: The mean SSIM and PSNR values were 0.4781(±0.0522) and 21.30(±1.51) dB, respectively. The pT2 protocol showed almost perfect agreement(ĸ=0.81) with the gold standard for disc position. The number of discordant cases was higher for normal disc position (17%) than for anterior displacement with reduction (2%) or without reduction (10%). The effusion diagnosis also showed almost perfect agreement(ĸ=0.88), with higher concordance for the presence (85%) than for the absence (77%) of effusion. Conclusion: The application of pT2 images for a TMJ MRI protocol useful for diagnosis, although the image quality of pT2 was not fully satisfactory. Further research is expected to enhance pT2 quality.

• Proceedings of the Korean Society of Computer Information Conference
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• 2019.07a
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• pp.329-330
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• 2019

스마트 유틸리티 네트워크 (SUN)는 가정, 빌딩, 공장 등에서 사용하는 전기, 수도, 가스와 같은 유틸리티를 효과적으로 관리할 수 있는 통신 네트워크 기술이다. 본 논문은 IEEE 802.15.4g 표준에 기반하는 Wireless-SUN 네트워크를 이용하여 원격 검침과 음성 동보 시스템을 구현하는 방안을 제시한다.

• Information and Communications Magazine
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• v.26 no.3
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• pp.9-15
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• 2009

전쟁양상이 네트워크 중심 전으로 발전되기 위해서는 기동중에도 멀티미디어 등 대용량의 정보를 실시간으로 소통할 수 있는 정보통신기반체계가 필수적으로 요구된다. 이러한 기반을 구축하기 위해 개발 중인 전술정보통신체계(TICN: Tactical Information and Communication Network)의 부체계 중 하나인 전술이동통신체계는 이동하는 전장가입자에게 음성서비스이외 전장상황 공유를 위한 대용량의 데이터 서비스를 제공해야 하므로, 주파수 효율성이 좋은 Mobile WiMAX 기술을 기반으로 구현되었다. 구현된 장비는 전장 환경과 비슷한 산악지형의 테스트베드에 설치되어서 운용 가능성을 검증하였다. 본고에서는 Mobile WiMAX기반의 전술이동통신체계의 가용성을 확인하기 위해 수행한 이론적인 분석과 테스트베드에서 확인한 성능에 대해 소개한다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.5 no.11
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• pp.2204-2220
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• 2011

Without providing a proper security measure to the handover procedure in Mobile WiMAX, several security attacks can be mounted. Even though security schemes have been previously proposed for this purpose, they are still vulnerable to several security attacks due to fatal design flaws. A newly proposed security scheme in this paper is based on the framework of authentication domain and concept of handover ticket. A method of establishing security associations within the authentication domain is proposed, and a lightweight security measure to protect the management messages associated with the handover is also proposed. Especially, using the handover ticket, the new security scheme can defend against a Redirection Attack arising from a compromised base station. The new security scheme is comparatively analyzed with the previous security schemes in terms of Replay, Session Hijacking, Man-In-The-Middle, and Redirection attacks.

• Proceedings of the KSRS Conference
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• 2002.10a
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• pp.209-215
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• 2002

Much effort has been made in the radiometric calibration of the ocean scanning multispectral imager (OSMI) since after the successful launch of KOMPSAT-1 in 1999. A series of calibration coefficients for OSMI detectors were obtained in collaboration with the NASA Sensor Intercomparison and Merger for Biological and Interdisciplinary (SIMBIOS) project office. In this study, we compare the OSMI level-2 products (e.g., chlorophyll-a concentration) calculated from the NASA cross-calibration coefficients with the SeaWiFS counterparts. Sample study areas are some of diagonostic data sites recommended by the SIMBIOS working group. We will present the preliminary results of this comparative study.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.40 no.5
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• pp.944-949
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• 2015

This study proposed a patch antenna with a MIMO structure which is applicable for wireless communication equipment by combining a single patch antenna with a multi port. The proposed MIMO patch antenna was designed through the TRF-45 substrate with a relative permittivity of 4.5, loss tangent equal to 0.0035 and dielectric high of 1.6 mm, and the center frequency of the antenna was 2.45 GHz in the ISM (Industrial Scientific and Medical) band. The proposed MIMO patch antenna had a 500 MHz bandwidth from 2.16 ~ 2.66 GHz and 24.1% fractional bandwidth. The return loss and VSWR were -62.05 dB, 1.01 at the ISM bandwidth of 2.45 GHz. The Wibro band of 2.3 GHz was -17.43 dB, 1.33, the WiFi band of 2.4 GHz was -31.89 dB, 1.05, and the WiMax band of 2.5 GHz was -36.47 dB, 1.03. The radiation patterns included in the bandwidth were directional, and the WiBro band of 2.3 GHzhad a gain of 4.22 dBi, the WiFi band of 2.4 GHz had a gain of 4.12 dBi, the ISM band of 2.45 GHz had a gain of 4.06dBi, and the WiMax band of 2.5 GHz had a gain of 3.9 6dBi.

• 한국ITS학회:학술대회논문집
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• 2010.05a
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• pp.87-91
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• 2010

• 대한핵의학회:학술대회논문집
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• 1986.05a
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• pp.123.2-124
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• 1986