• Journal of electromagnetic engineering and science
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• v.9 no.1
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• pp.17-24
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• 2009

In recent years, OFDMA(orthogonal frequency division multiple access) and SC-FDMA(Single Carrier Frequency Division Multiple Access) have been widely studied for the uplink of a mobile communication system. In this paper, PAPR(Peak-to-Average Power Ratio) and BER(Bit Error Rate) performance of the OFDMA and SC-FDMA systems are studied in relation to the uplink of a mobile communication system. Three kinds of sub-carrier allocation methods in the OFDMA system and 2 kinds of sub-carrier allocation methods in SC-FDMA system are suggested to compare and improve system performance. Simulation results show that in the OFDMA system, the first sub-band allocation method has better PAPR reduction performance than the other methods. In the SC-FDMA system, the distributed allocation method offers similar P APR, compared with the sub-band allocation method. P APR can be further reduced by adding a spectrum shaping filter with an appropriate roll of factor. Furthermore, it is found that on average, SC-FDMA can reduce the PAPR by more than 5 dB compared to OFDMA, when the total sub-carrier number is 1,024 and the sub-carrier number allocated to each user changes trom 8 to 512. Because of the frequency diversity and low PAPR characteristics, SC-FDMA system of the distributed sub-carrier allocation method can achieve better BER performance than the OFDMA system.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.16 no.9
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• pp.1892-1897
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• 2012

In this paper, efficient CNU(Check Node Update) algorithms are analyzed for high speed LDPC decoding in DVB-S2 standard. In aspect to CNU methods, there are some kinds of CNU methods. Among of them, MP (Min Product) method is quite often used in LDPC decoding. However MP needs LUT (Look Up Table) that is critical path in LDPC decoding speed. A new SC-NMS (Self-Corrected Normalized Min-Sum) method is proposed in the paper. NMS needs only normalized scaling factor instead of LUT and compensates the overestimation of MP approximation. In addition, SC method is proposed. It gives a faster convergence toward a decoded codeword. If a message change its sign between two iterations, it is not reliable and to avoid to propagate noisy information, its module is set to 0. The performance of SC-NMS has a little degrade compare to MP by 0.1 dB, however considering computational complexity and decoding speed, SC-NMS algorithm is optimal method for CNU algorithm.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.7A
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• pp.477-484
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• 2003

In this paper, we compared and analyzed the influence of the fading index and the number of branch of diversity in the Nakagami-m fading channel environment when the MRC diversity and the hybrid SC/MRC are applied to the DS/CDMA system. We considered that the number of branches were 2,3, and 4, respectively and applied an individual diversity type according to the number of branches, when nakagami fading index(m) were 1 and 2. We found that when the Nakagami fading index m is small, that is to say, when fading is inferior, the application of a hybrid SC/MRC diversity Rake receiver is efficient; however, when the fading environment is good, the application of the MRC diversity Rake receiver is efficient. As a result, we verified that when the actual communication environment is inferior, the hybrid SC/MRC diversity that selects a strong signal to be received on an individual number of branches could replace the MRC diversity, as a method to achieve a similar performance by reducing the complexity of the system.

• Journal of Radiopharmaceuticals and Molecular Probes
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• v.8 no.1
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• pp.9-15
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• 2022

Anti-cancer and therapeutic effects using therapeutic radioisotopes have been demonstrated by various studies, and it is well-known that therapeutic radioisotopes are useful in cancer treatment. Recently, one of the therapeutic radioisotopes, scandium is emerging as a radioisotope applicable to PET imaging (⁴³Sc, ⁴⁴Sc) and therapy (⁴⁷Sc) in cancer theranostic approach. However, ⁴⁷Sc has little known radiobiological and therapeutic efficacy compared to other therapeutic radioisotopes. Here, we investigated the quality and therapeutic efficacy of ⁴⁷Sc radioisotope produced by our production/isolation technology at the research reactor 'HANARO' in KAERI (Korea Atomic Energy Research Institute). We showed that the therapeutic efficacy of ⁴⁷Sc, produced by our production/isolation technology, effectively suppressed epidermal growth factor receptor (EGFR)-targeted non-small cell lung cancer (NSCLC) cells. Consequently, these results suggest that the high quality of the produced ⁴⁷Sc by our production/isolation technology enables the development of therapeutic strategies for cancer treatment and radiopharmaceuticals using ⁴⁷Sc.

• Review of KIISC
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• v.20 no.6
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• pp.96-99
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• 2010

ISO/IEC JTC1 SC27는 IT 정보보호에 관한 국제표준 제정 활동을 하는 국제기구로서, 다섯 개의 WG(Working Group)으로 구성되어 있으며, 현재 WG4는 WG1의 정보보호관리체계(ISMS), WG5에서 다루어지고 있는 인증(Authentication), 프라이버시(Privacy) 등과 연계하여, 정보보호 관련 국제표준을 개발 및 제정하고 있다. 본 논문은 2010년 10월 4일부터 8일까지 베를린(Berlin)에서 개최한 회의에서 WG4에서 다루어지고 있는 네트워크 보안 국제표준기술 동향과 표준화에 대한 개요를 소개하고, ISO/IEC JTC1 SC27 WG4 Plenary에서 필자가 제안하여 SP(Study Period) 단계로 승인된 표준안건의 동향과 전망에 대해 소개하고자 한다.

• Review of KIISC
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• v.26 no.4
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• pp.6-10
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• 2016

기업의 개인정보보호 수준을 강화하기 위한 개인정보보호관리체계 인증을 구축하기 위해서는 개인정보관리체계를 위한 추가 요구사항, 보안 측면의 통제, 프라이버시 측면의 통제가 요구된다[1,2]. 국제표준화위원회/전기위원회 합동위원회 1의 정보보호기술연구반 신원 관리 및 프라이버시 작업반 (ISO/IEC JTC 1/SC 27/WG 5)에서는 개인정보보호를 위한 여러 국제 표준을 개발하고 있다[18, 32, 22]. 본 논문에서는 작업반 1과 작업반 5에서 2016년 4월 SC27 회의에서 논의된 개인정보보호 관련 주요 표준화 이슈와 대응 방안을 제시한다.

• Journal of the Ergonomics Society of Korea
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• v.28 no.3
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• pp.135-145
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• 2009

This study surveyed standardization activities of the International Standard Organization (ISO) Technical Committee 159 (TC 159) (ergonomics) in the year 2008. The subcommittee 1 (SC 1) dealing with general ergonomics principles produced one committee draft (CD). The subcommittee 3 (SC 3) dealing with anthropometry and biomechanics systematically reviewed two ISO standards issued in 2003 and 2004 respectively. The subcommittee 4 (SC 4) dealing with ergonomics of human system interaction issued 11 final draft international standards (FDIS), 3 draft international standards (DIS), 4 CDs, and 4 new work item proposals (NWIP). The SC 4 also systematically reviewed 10 international standards due on the year 2008. The subcommittee 5 (SC 5) dealing with ergonomics of the physical environment issued one FDIS, 3 CDs, and one NWIP. This paper summarized the major features of the FDIS approved by each subcommittee of TC 159 for publication in the year 2008.

• Journal of the Korean Society of Marine Environment & Safety
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• v.21 no.1
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• pp.47-56
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• 2015

Under the conditions of invested actual changes of heeling angles during MV Sewol's sinking, this study proposes passengers' evacuation scenarios, which are based on the assumption of normal orders of evacuation being given to the passengers, and evaluates using a marine-specialized human evacuation simulation tool. As results, when the heeling angle is set as 0 degree or 30 degree, it is found out that almost every passengers can success to evacuate to the musterstations, even though the evacuation times are different depending on the scenarios and the walking speeds. Meanwhile, when the heeling angle is varied as the Sewol incident, 3.1 %(Scenario Sc-Va which set chutes on port side as evacuation routes), 11.1 %(Sc-Vb, every open decks of port side as evacuation routes) and 20.0 %(Sc-Vc, every open decks of port and AFT sides as evacuation routes) among 476 passengers can successfully reach to the musterstations from their cabins with the condition of average walking speed as 2.04 m/s on flat. And only 0.8 %(Sc-Va), 3.8 %(Sc-Vb) and 10.7 %(Sc-Vc) can success to evacuate with the condition of average walking speed as 1.48 m/s on flat.

• Journal of Integrative Natural Science
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• v.4 no.4
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• pp.311-314
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• 2011

Application of self-assembled monolayers (SAMs) to the fabrication of organic thin film transistor has been recently reported very often since it can help to provide ohmic contact between films as well as to form simple and effective electrode pattern. Accordingly, quality of these ultra-thin films is becoming more imperative. In this study, in order to manufacture a high quality SAM pattern, a hydrophobic alkylsilane monolayer and a hydrophilic aminosilane monolayer were selectively coated on $SiO_2$ surface through the consecutive procedures of a micro-contact printing (${\mu}CP$) and dip-coating methods under extremely dry condition. On a SAM pattern cleaned with SC1 solution immediately after ${\mu}CP$, poly(3,4-ethylenedioxythiophene) (PEDOT) source and drain electrode array were very selectively and nicely vapour phase polymerized. On the other side, on a SC1-untreated SAM pattern, PEDOT array was very poorly polymerized. It strongly suggests that the SC1 cleaning process effectively removes unwanted contaminants on SAM pattern, thereby resulting in very selective growth of PEDOT electrode pattern.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.46 no.1
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• pp.72-82
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• 2009

In OFDMA systems, cyclic delay diversity can improve the system performance due to diversity effects. However, applying cyclic delay diversity to block-hopping SC-FDMA systems can affect the performance in two contrary ways: positive effect due to increased frequency diversity and negative effect caused by increased frequency selectivity. Hence, the delay value for cyclic delay diversity should be carefully selected to maximize the system performance. This paper discusses these two contrary effects and proposes a method of determining the delay value of cyclic delay diversity for block-hopping SC-FDMA systems.