• Journal of the Institute of Electronics and Information Engineers
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• v.53 no.8
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• pp.76-82
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• 2016

In this paper, we evaluated shielding effectiveness (SE) of carbon nanotube (CNT) film using near field scanning (NFS) in near field analysis. We adopted CNT film with deposit carbon density of 5% and thickness of 1mm for evaluation of shielding characteristic. Using a test coupon analogized to an actual IC package, we measured SE according to measuring position and SE according to distances between the CNT film and the test coupon. As a result, the measured SE in the near field varied with frequency. Especially, the measured electric field SE in the center of the test coupon is better than that of the measured edge point of the test coupon where it is affected by fringing effect. The results show that the measured SE in the near field is affected not only by frequency but also by measurement environment such as position and height of the probe and height of shielding film. In conclusion, we should choose proper methods for SE measurement considering interference distance in the electronic control system because there is little correlation between the proposed evaluation method in the near field and ASTM D 4935-10.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2004.06a
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• pp.419-424
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• 2004

Various radiation counters have been using to determine radioactivity of radwastes for disposal. A radiation counting system was set up using a radiation detector chosen in this study and its stability was investigated through the periodic determination of background and counting efficiencies in accordance with a quality control program to increase the confidence level. The average background level for the $\gamma$-spectrometer was 1.59 cps and the average counting level for the standard sample was 45248 Ops within $2{\sigma}$ confidence levels. The average alpha background level for the low background ${\alpha}{\beta}$ counting system was 0.31 cpm and the efficiency for alpha counting was 34.38%. The average beta background level for the ${\alpha}{\beta}$ counting system was 1,30 cpm and the efficiency for beta counting was 46.5%, The background level in the region of 3H and 14C for the liquid scintillation counting system was 2.52 and 3.31 cpm and the efficiency for alpha counting was 58.5 and 95.6%, respectively. The minimum detectable activity for the$\gamma$-spectrometer was found to be 3.2 Bq/$m\ell$ and 3.8 Bq/$m\ell$ for the liquid scintillation counter, and 20.5 and 23.0 Bq/$m\ell$, respectively for the $\alpha$ and $\beta$ counting system.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2005.04a
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• pp.359-362
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• 2005

알파전용 액체섬광기를 이용하여 지하수내 Polonium을 간편하고 신속하게 측정하는 방법을 연구하였다. 추출섬광용액으로 HDEHP, TNOA, TOPO 또는 NDA 등을 사용하지만 본 실험에서는 POREX(77g TOPO, 180g Naphthalene, 4.0g PBBO/1L Toluene)를 사용하였다. 지하수의 액상을 $1M\;H_2SO_4-0.01M\;NaCl$로 맞추어주고 0.012M POREX를 추출액으로 사용하여, 분리 추출하므로써 실험의 추출효율 및 재현성을 조사하였다. 위 조건에서의 Polonium 분배계수는 $10^4$ 이상으로 알려져 있다. 표준물질인 Po-209(NIST SRM 4326)를 Po의 측정효율 및 추출효율을 조사하는데 이용하였다. 실제 지하수에 위 실험방법을 적용하여 지하수의 Polonium을 측정하였다.

• Journal of the Korea Society of Computer and Information
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• v.10 no.4 s.36
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• pp.375-384
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• 2005

As the development of information communication technology and thus the growth of security incidents, there has been increasing demand on developing methodologies and tools for measuring the information security level of organizations for the efficient security management. However, most works from foreign countries are not realistic in constructing the checklists, moreover their tools provide neither the ease of use nor the inexpensiveness, and most domestic works are not properly considering the characteristics of the organizations when measuring the information security level. In this study, an efficient information security levelling tool is suggested, which applies the multiple variable weights for security levelling according to the characteristics of organizations and the fuzzy technique to reduce the user's subjectivity and the genetic algorithm to establish the security countermeasure.

• Journal of Korean Society of Transportation
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• v.31 no.2
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• pp.11-19
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• 2013

This study analyzed relative efficiencies of fourteen airports in Korea with radial and non-radial approaches such as DEA(Data Envelopment Analysis) and SBM(Slack Based Measure) from 2004 to 2011. To suggest an improvement scheme for these airports, we analyzed slack airports and compared then with respective reference airports. To measure efficiency, we used the length of runway, the number of employees, and the size of terminal as input factors, and the number of passengers, the amount of cargo, and the number of flights as output factors. The analysis results showed that efficiencies of most airports had been decreasing and that the gap between efficient airports and inefficient airports was widening. Additionally, most airports had much slacks in its terminal size. It meant that they had been operated with a size not proportionate to their demands and that it is a major cause of inefficiency.

• Journal of the Korea Convergence Society
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• v.13 no.3
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• pp.217-225
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• 2022

We analyzed efficiency and productivity of the Indian non-life insurance market affected by the COVID-19 pandemic from 2020. Using data envelopment analysis(DEA), we examined non-life insurance companies selling health insurance products in India from FY2013 to FY2019. We found the followings. First, average efficiency of the entire non-life insurance industry worsened in the beginning yet improved later. Second, analyzing the efficiency measures by group, we found that private insurance companies had the highest efficiency, followed by state-run insurance companies and pure health insurance companies. Third, average annual productivity growth rate of companies operating distance selling channels including telemarketing is higher than that of traditional face-to-face channels. During and after the COVID-19 pandemic, therefore, Indian non-life insurance companies should focus their resources and efforts on the development of distance selling channels when establishing business strategies. Besides, it would be interesting to extend our analysis to the post-coronavirus period and we leave this for future research.

• Proceedings of the KOR-KST Conference
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• 2002.02a
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• pp.3-13
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• 2002

미국의 전체 버스시스템의 횡단면자료를 가지고 민간위탁운영과 정부직영을 비교 분석한 결과, 민간위탁운영과 정부직영의 버스서비스 공급에 있어 효과성과 공적책무성 측면에서 중요한 차이점이 있는 것으로 분석되었다. 효율성 비교분석에서는 효율성 측정을 위해 어떤 지표를 사용하느냐에 따라 민간위탁과 정부직영중 어느 버스운영시스템이 더 효율적인지에 대해 전혀 다른 결과를 보였다. 즉 효율성은 어느 운영시스템이 더 효율적이라고 단정할 수 없었다. 효과성분석에서는 정부직영이 민간위탁보다 더욱 효과적인 것으로 분석되었다. 공적책무성 분석에서는 민간위탁운영은 공공성의 소극적지표인 공적책무성을 정부직영에 비해 감소시키는 것으로 분석되었다.

• Proceedings of the Korean Information Science Society Conference
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• 2007.06b
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• pp.333-338
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• 2007

시스템 가상머신 환경은 높은 하드웨어 효율성과 높은 보안을 요구하는 시스템에서 그 사용이 점차 늘어나고 있다. 최근 많이 알려진 하이퍼바이저 가상머신 시스템은 높은 아이솔레이션과 보안성을 보장하나 각 게스트 운영체제 별로 운영체제 이미지를 가지기 때문에 하드웨어 효율성이 떨어지는 반면, 컨테이너 기반 가상머신 시스템은 운영체제 이미지의 공유로 인하여 높은 자원 효율성과 확장성을 가진다. 그러나 메모리 자원의 아이솔레이션에 대하여 취약점을 갖는 문제점을 안고 있다. 본 논문에서는 컨테이너 기반 가상머신 시스템에서 동적으로 각 가상머신별로 메모리 사용량 증가에 따른 페이지 히트율-곡선(Hit-Ratio-Curve)을 측정하였다. 이 곡선을 관찰해 보면 각 가상머신의 메모리 필요량을 알 수 있으며 이를 기반으로 메모리 자원을 할당하게 될 경우 효과적으로 메모리 자원의 아이솔레이션을 제공할 수 있게 된다. 본 논문에서는 대표적인 컨테이너 기반 가상머신인 리눅스 VServer가 적용되어 있는 리눅스 2.6.17 커널에 직접 구현하였으며, Lmbench 및 리눅스 커널 컴파일 등을 통하여 오버헤드를 측정하였고 $1.6{\sim}7.2%$의 적은 오버헤드로 이를 측정할 수 있음을 확인하였다.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2005.10a
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• pp.410-416
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• 2005

생물학적 통풍법은 유류오염 지역에 자주 적용되는 정화공법이다. 이 과정은 지중에 산소를 충분히 공급함으로서 토착 미생물에 의한 오염성분의 분해를 가능하게 한다. 따라서 이 공법의 적용시 공정진행에 따른 공법의 효율성 분석과 장기적인 정화효율 예측을 위한 지중 가스성분의 모니터링 시스템 도입이 매우 중요하다. 그러나 우리나라에서는 아직 그 적용사례가 보고된 바 없다. 따라서 본 연구에서는 현장에서 토양가스 성분의 변화를 모니터링할 수 있는 시스템을 개발하여 적용한 사례를 시스템의 구성과 측정방법, 관측결과를 중심으로 소개하였다. 현장적용 결과는 토양가스 모니터링 시스템은 운용 시작 후 6개월동안 센서나 측정장비에서 문제가 발생되지 않았으며, 공정관리를 위한 공법효율성 분석에 필요한 자료를 지속적으로 제공하고 있다.

• Journal of Radiation Protection and Research
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• v.21 no.3
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• pp.167-173
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• 1996

The calibration method for the detection efficiency of solid state track detector to alpha is presented, and the detection efficiency of CN-85 and LEXAN to alpha is measured by this method. The results are 97% and 57% in CN-85 and LEXAN, respectively. The reason for a better result in CN-85 in not only the high sensitivity but also the low energy dependency with comparing for LEXAN. The peak detection efficiency is 3MeV and 1.8MeV in CN-85 and LEXAN, respectively.