• 한국항행학회논문지
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• 제22권5호
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• pp.409-414
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• 2018

광역 차분위성항법시스템의 서비스 영역을 기준국 네트워크 외부로 확장하기 위해서는 전리층 보정 정보의 외삽이 필수적이다. 본 논문에서는 전리층 보정 영역 확장을 위한 인공 신경망을 설계하고 이에 대한 성능분석을 수행하였다. 인공 신경망 입력으로 사용되는 일/년별 주기함수, 태양흑점개수, 자기장 인덱스(Ap)의 개별 요소들이 전리층 외삽 추정 성능에 미치는 영향을 분석하였다. 신경망의 구성에 있어서는 은닉 층의 수 및 뉴런 개수 변화에 따른 성능 분석을 수행하였다. 분석결과를 바탕으로 신경망을 구현하고 태양활동 극대기(2014년)의 고위도와 저위도 지역에서의 전리층 추정 결과를 보였다.

• Interdisciplinary Bio Central
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• 제3권3호
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• pp.12.1-12.3
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• 2011

Bioinformatics tools and databases are useful for understanding and processing various biological data. Numerous resources are being published each year. It is not a trivial task to find up-to-date relevant tools and databases. Moreover, no server is available to provide comprehensive coverage on bioinformatics resources in all biological fields. Here, we present a directory server called IntoPub that provides information on web resources. First, we downloaded XML-formatted abstracts containing web URLs from the NCBI PubMed database by using 'ESearch-EFetch' function in the NCBI E-utilities. The information is obtained from abstracts in the PubMed by extracting 'www' or 'http' prefixes. Then, we cu-rate the downloaded abstracts both in automatic and manual fashion. As of July 2011, the IntoPub database has 12,118 abstracts containing web URLs from 174 journals. Our anal-ysis shows that the number of abstracts containing web resources has increased signifi-cantly every year. The server has been tested by many biologists from several countries to get opinion on user satisfaction, usefulness, practicability, and ease of use since January 2010. In the IntoPub web server, users can easily find relevant bioinformatics resources, as compared to searching in PubMed. IntoPub will continue to update and incorporate new web resources from PubMed and other literature databases. IntoPub, available at http://into.kobic.re.kr/, is updated every day.

• Archives of Plastic Surgery
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• 제33권1호
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• pp.53-60
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• 2006

The current authors performed two-stage ear reconstruction of microtia using autogenous costal cartilage combined with canaloplasty of the acoustic meatus in a team approach. In the first stage, lobule transposition, fabrication of the cartilage framework, and implantation of the framework were peformed. In the second stage, elevation of the auricle, cartilage graft for posterior auricular sulcus, coverage with the mastoid fascia flap and skin graft, and concha excavation were performed. The canaloplasty was combined simultaneously in patients with radiologic and audiometric evidence of cochlear function in the second stage. A total of 36 consecutive patients with congenital microtia were treated from 1998 to 2003. Among them, 27 patients(male: 18, female: 9) ranging from 7 to 43 years old were combined with canaloplasty. The follow-up period was one year to 5 years. Thirteen patients exhibited improved hearing over 30 dB PTA(pure tone average), 9 patients below 30 dB, and 5 patients with no improvement. Complications related to the canaloplasty were chronic drainages of the auditory meatus and meatal stenosis. Lobule type deformity combined with the canaloplasty showed higher complications than concha type. Therefore, in the lobule type, meticulous manipulation is necessary to reduce complications after the canaloplasty.

• Bulletin of the Korean Chemical Society
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• 제35권2호
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• pp.581-586
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• 2014

The most stable adsorption structures and their corresponding energies of 4-pyridone, 4-hydroxypyridine, 2-pyridone and 2-hydroxypyridine have been investigated by Density Functional Theory (DFT) calculation and high-resolution photoemission spectroscopy (HRPES). We confirmed that between the two reaction centers of 4- and 2-pyridone, only O atom of carbonyl functional group can act as a Lewis base while both the two reaction centers of 4- and 2-hydroxypyridine (tautomers of 4- and 2-pyridone) can successfully function as a Lewis base. On the other hand, owing to their molecular structures, there is a remarkable difference between the adsorption structures of 4- and 2-hydroxypyridine. Through the analysis of the N 1s and O 1s core level spectra obtained using HRPES, we also could corroborate that two different adducts coexist on the surface at room temperature due to their activation energy investigating the coverage dependent variation of bonding configurations when these molecules are adsorbed on the Ge(100) surface.

• ETRI Journal
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• 제41권6호
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• pp.703-714
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• 2019

Many use cases have been presented on providing convenience and safety for vehicles employing wireless access in vehicular environments and long-term evolution communication technologies. As the 70-MHz bandwidth in the 5.9-GHz band is allocated as an intelligent transportation system (ITS) service, there exists the issue that vehicular communication systems should not interfere with each other during their usage. Numerous studies have been conducted on adjacent interfering channels, but there is insufficient research on vehicular communication systems in the ITS band. In this paper, we analyze the interference channel performance between communication systems using distribution functions. Two types of scenarios comprising adjacent channel interference are defined. In each scenario, a combination of an aggressor and victim network is categorized into four test cases. The minimum requirements and conditions to meet a 10% packet error rate are analyzed in terms of outage probability, packet error rate, and throughput for different transmission rates. This paper presents an adjacent channel interference ratio and communication coverage to obtain a satisfactory performance.

• 한국환경과학회지
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• 제25권10호
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• pp.1407-1415
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• 2016

In this study, we investigated the relationship between noise reduction and the community structure of nine groups of typical plant communities as well as the reduction in noise at different frequencies. The semantic differential method was adopted to explore the perception of noise reduction. The results indicated that there was a significantly positive correlation between noise reduction and coverage, a significantly negative correlation between noise reduction and bifurcate height, and a negative correlation between noise reduction and bare rate. However, there was no significant correlation between noise reduction and height, diameter at breast height, or crown width. The reduction of middle-frequency noise was better than that of low- and high-frequency noise. The indicators "quiet" and "calm" showed that plant communities could reduce the noise perceived by humans. However, overly dense woodland caused nervousness, fear, depression, and other negative effects. Relatively open environments and those with large forest gaps obtained the highest evaluation.

• 한국통신학회논문지
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• 제34권7A호
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• pp.530-539
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• 2009

Wireless Relaying is a promising solutions to overcome the channel impairments and provides high data rate coverage that appear for beyond 3G mobile communications. In this paper we present end to end BER performance of dual hop wireless communication systems equipped with multiple Decode and Forward relays over Rayleigh fading channel with the best relay selection. We compare the BER performance of the best relay with the BER performance of single relay. We select the best relay based on the end to end channel conditions. We further calculate the outage probability of the best relay. It is shown that the outage probability of the best relay is equivalent to the outage probability when all relays take part in the transmission. We apply Orthogonal Space Time Block coding(OSTBC) at the source terminal. Numerical and simulation results are presented to verify our analysis.

• 한국신뢰성학회지:신뢰성응용연구
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• 제17권2호
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• pp.122-128
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• 2017

Purpose: To investigate the corrosion inhibition effect of the natural spearmint oil extracted from Mentha Spicata plants on 304 stainless steel in different concentrations of hydrochloric acid. Method: The anti-corrosive effect has been investigated in 0.5m, 1m and 2m HCl using weight loss test and electrochemical polarization method as a function of inhibitor concentration and immersion time in strong chloride environment. The surface morphology was analysed by scanning electron microscopy (SEM). Results: The corrosion rate of steel decreased and inhibition efficiency increased with the increase in inhibitor concentration. Microscopic evaluation revealed significant corrosion in the specimens immersed in uninhibited conditions. Potentiodynamic polarization test results showed an increase in corrosion potential (Ecorr) and decrease in corrosion current (icorr) value with increasing concentration of inhibitor. Conclusions: Immersion of steel in higher concentration of inhibitor resulted in greater surface coverage value and hence lesser number of surface corrosion sites/pores were formed; thus lowering the corrosion rate.

• 한국컴퓨터정보학회논문지
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• 제3권4호
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• pp.19-26
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• 1998

이동 데이터베이스 체계는 이동 전산처리 환경에서 데이터베이스 체계를 기반으로한 정보처리이다. 이동 데이터베이스 체계에서 이동 거래 호스트가 거래를 처리하는 동안 다른 신호영역으로 이동할 때 새로운 데이터베이스 서버에 통신망 주소로 변경해야한다. 이러한 것을 거래 서비스 통화채널 변경이라고 한다. 본 논문에서는 이동 데이터베이스 체계에서 이러한 거래 서비스 통화채널 변경의 적당한 기능을 제공하기 위한 거래처리 기법을 제안한다 이 기법은 거래 처리 서비스 통화채널이 발생할 때 새로운 데이터베이스 서버에서거래를 처리하자는 조정자 이주 원리를 적용하였다. 결국, 제안된 기법은 이동 데이터베이스에 거래를 처리하기 위한 메시지 이동을 최소화함으로서 시스템 성능을 향상시킬 수 있다.

• 한국통신학회논문지
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• 제36권6B호
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• pp.738-743
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• 2011

본 고에서는 각 센서에 필요한 에너지를 공급하는 장치를 포함한 센서 네트워크 시스템을 고려하고, 에너지 공급 장치의 설치 및 운용 비용을 최소화하는 방법을 제안한다. 센서와 에너지 공급원이 정방형으로 배치되는 구조하에서 센서 노드의 밀도, 에너지 공급장치당 센서 노드 커버 범위 등에 따라 에너지 공급 장치의 설치 및 운용비용을 함수화한다. 또한 주어진 센서 노드밀도 환경에서 총 비용을 최소화하는 에너지 공급장치당 센서 노드 커버 범위를 결정하여 에너지 공급장치가 포함한 센서 네트워크의 배치를 최적화한다. 모의 실험을 통해 기존 방법에 비해 제안된 방법이 약 19%의 센서 네트워크 비용을 절감하는 효과를 가짐을 보인다.