• Journal of the Korean Chemical Society
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• v.23 no.2
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• pp.75-79
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• 1979

The frontier orbital energy, superdelocalizability and charge density of a series of benzologous pyridine ligands have been calculated by using HMO. According to ${\Delta}E_{\pi}$ of ligands on the basis of the above results, it is concluded that the stabilities are in the order of 1,10-Phen > 4,5-Phen > 1,5-Phen > 8-Hox > Hox-azoquinolinato. And also, the reactivities of electrophilic, nucleophilic and radical reaction, and bond strength have been respectively studied by superdelocalizabilities and charge densities.

• Journal of KIISE:Software and Applications
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• v.26 no.3
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• pp.441-451
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• 1999

본 논문에서는 퍼지숫자를 정렬하는 새로운 방법을 제안한다. 제안하는 방법은 사용자의 관심도나 선호도를 반영할 수 있는 방법을 제공하며, 퍼지숫자의 전체적인 가능성분포를 고려하는 평가함수를 방법은 사용자가 제사한 퍼지 집합과 만족도 함수(satisfaction fuction)를 이용하여 정렬 대상이 되는 퍼지숫자를 평가한 후 그 평가값에 따라서 순위를 정하게 된다. 만족도 함수는 두 퍼지숫자의 비교를 위해서 이전에 제안된 방법으로 퍼지숫자의 전체적인 가능성을 고려하는 특징이 있다. 본 논문에서는 제안하는 방법을 퍼지숫자 정렬에 적용한 예와 기존의 방법과 비교한 결과를 보이며, 응용 예로서 의사결정의 문제에 적용한 결과를 제시한다.

• Proceedings of the Korean Information Science Society Conference
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• 2006.06a
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• pp.127-129
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• 2006

본 논문은 종양을 주입한 쥐의 FDG-PET영상에서 정상세포보다 포도당대사가 활발한 종양조직의 3차원적 위치를 파악하고 잔여암 전이여부를 판별하기 위한 3차원 볼륨 가시화기법을 제안한다. 종양조직과 주변조직의 시각적 대비를 크게 하기 위해 명암도 분포에 따라 조직을 여러 클러스터로 나눈 후, 적응적 투명도 전이함수를 사용하였다. 관심영역을 불투명하게 표현하고 조직간 투명도 변화량을 크게 줌으로써 잡음이 심한 PET 영상에서 전경영역과 배경영역을 구분할 수 있었고, 명확한 시각대비 결과를 얻을 수 있었다. 추후 명암도값 외에 영암도 기울기, 관심영역 우선순위 등을 고려한 다차원 전이함수기법으로 확장함으로써 종양영역의 경계를 더욱 강조할 수 있을 것으로 기대된다.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2012.07a
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• pp.138-139
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• 2012

본 논문에서는 보다 정밀한 깊이 정보를 추출하기 위하여, 밝기 차이에 강인한 스테레오 정합 기법을 개발한다. 우선 촬영된 환경에 따라 발생하는 스테레오 영상의 노출 차이를 보상하기 위하여, 전체 영상에 대하여 전역적으로 히스토그램 기반의 3 차원 누적 분포 함수를 계산한다. 계산된 3 차원 누적 분포 함수를 기반으로 순위 영상을 생성하고, 밝기 기반의 강인한 초기 정합을 수행한다. 다음으로 지역적인 밝기 변화에 강인하도록, 초기 깊이 정보를 바탕으로 EM 알고리즘을 수행하여 객체와 배경에 해당되는 깊이 정보를 분리한다. 분리된 영역 정보를 기반으로 각각의 영역의 대하여 다시 히스토그램 기반의 3 차원 누적 분포 함수를 계산한다. 이를 기반으로 최종적으로 전경과 배경의 차등적인 정합을 수행하여 지역적인 밝기 차이에 강인한 스테레오 정합기법을 개발한다. 다양한 실험을 통하여 본 논문에서 제안하는 기법의 성능을 확인한다.

• Journal of the Korean Data and Information Science Society
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• v.26 no.6
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• pp.1225-1238
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• 2015

In this research, we fit various survival models and conduct tests and estimation for the hazard change-point with the rectal cancer data. By the log-rank tests, at significance level ${\alpha}=0.10$, survival functions are significantly different according to the uniporter of glucose (GLUT1), clinical stage (cstage) and pathologic stage (ypstage). From the Cox proportional hazard model, the most significant covariates are GLUT1 and ypstage. Assuming that the rectal cancer data follows the exponential distribution, we estimate one hazard change-point using Matthews and Farewell (1982), Henderson (1990) and Loader (1991) methods.

• Environmental and Resource Economics Review
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• v.30 no.4
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• pp.581-605
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• 2021

The purpose of this study is to provide basic data for improving energy efficiency by estimating the regional energy efficiency in Korea using the stochastic frontier approach beyond the energy intensity that has been traditionally used as an indicator of energy efficiency. In this paper, energy efficiency and energy intensity efficiency were estimated as a stochastic distance function from 1998 to 2018 for 16 cities and provinces in Korea. In addition, the robustness of energy efficiency according to the capital stock estimation methods which had been mixed in previous studies was reviewed. As a result of the analysis, there is a significant change in regional rankings according to the three energy efficiency indicators, so they should be used complementary to each other. Second, while the energy efficiency improved little by little over time, the energy intensity efficiency decreased slightly though. Lastly, energy efficiency by region according to the capital stock estimation method was not robust. Care must be taken in estimating capital stock, which is important in economic analysis.

• The Journal of the Acoustical Society of Korea
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• v.21 no.8
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• pp.735-743
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• 2002

In this paper, we propose three new text-independent speaker identification methods. At first, to exclude the frames not having enough features of speaker's vocal from calculation of the maximum likelihood, we propose the FS(Frame Selection) method. This approach selects the important frames by evaluating the difference between the biggest likelihood and the second in each frame, and uses only the frames in calculating the score of likelihood. Our secondly proposed, called the Hybrid, is a combined version of the FS and WMR(Weighting Model Rank). This method determines the claimed speaker using exponential function weights, instead of likelihood itself, only on the selected frames obtained from the FS method. The last proposed, called MWMR (Modified WMR), considers both original likelihood itself and its relative position, when the claimed speaker is determined. It is different from the WMR that take into account only the relative position of likelihood. Through the experiments of the speaker identification, we show that the all the proposed have higher identification rates than the ML. In addition, the Hybrid and MWMR have higher identification rate about 2% and about 3% than WMR, respectively.

• The Journal of the Korea Contents Association
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• v.11 no.11
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• pp.521-535
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• 2011

The purpose of this study is to analyze the priority of curriculums on students preparing to become flight attendants using paired t-test, Borich method, and Herschknowiz's criticality function. As a result of this study, it was discovered that what flight attendants and students needed to study the most were foreign language subjects as English, Chinese, and Japanese. Therefore, a department of universities related to airline service should develop new curriculum to adapt to the trend of globalization. Also, flight attendants need curriculum including subjects related to tourism as an introduction to airline service. This means that the role of flight attendants needs to be expanded and specialized. In conclusion, a department related airline service should try to elevate its quality of education and design curriculum which will help flight attendants become specialists in their field.

• Journal of the Institute of Electronics and Information Engineers
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• v.52 no.11
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• pp.12-19
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• 2015

In network-centric warfare, the communication network has played a significant role in defeating an enemy. Especially, the urgent and important data should be preferentially delivered in time. Thus, we proposed a priority MAC protocol based on CSMA/CA with Binary Exponential Back-off for tactical wireless networks. This MAC protocol suggested a PCW(Prioritized Contention Window) with differentiated back-off time by priority and a RBR(Repetitive Back-off Reset) to reset the remaining back-off time. The results showed that this proposed MAC has higher performance than those of DCF(Distributed Coordination Function) in the transmission success rate and the number of control packet transmission by reducing the packet collision. Thus, it produced more effective power consumption. In comparison with DCF, this proposed protocol is more suitable in high-traffic network.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.2
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• pp.76-84
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• 2021

The quality assurance activities can detect the factors that affect the quality based on risk identification in the course of mass production. Risk identification is conducted with risk analysis, and the risk analysis method for the rotorcraft landing system is selected by failure mode effects analysis (FMEA). FMEA is a method that detects the factors that can affect the product quality by combining severity, occurrence, and detectability. The results of FMEA were prioritized using the risk priority number. On the other hand, these methods have certain shortcomings because the severity, occurrence, detectability are weighted equally. Dempster-Shafer evidence theory can conduct uncertainty analysis for the opinions with personal reflections and subjectivity. Based on the theory, the belief function and the plausibility function can be formed. Moreover, the functions can be utilized to evaluate the belief rate and credibility. The system is exposed to impact during take-off and landing. Therefore, experts should manage failure modes in the course of mass production. In this paper, FMEA based on the Dempster-Shafer evidence theory is discussed to perform risk analysis regarding the failure mode of the rotorcraft landing system. The failure priority was evaluated depending on the factor values. The results were derived using belief and plausibility function graphs.