• 응용통계연구
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• 제31권2호
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• pp.241-251
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• 2018

마이크로어레이 자료의 유전자집합분석은 개별유전자분석에 비해 검정력도 높일 수 있고 결과 해석이 쉬워서 이에 대한 연구가 활발히 진행되어 왔다. 표현형에 따라 유의한 차이를 보이는 유전자집합의 검색은 검정통계량들이 유도된 배경에 따라 결과에 차이를 보이지만 대체적으로 t-통계량의 제곱합을 이용한 순열검정이 제일 무난한 방법으로 여겨진다. 그러나 유전자집합분석에서 다중검정은 필수이고 많은 집합들의 유의성에 변별력을 주기 위해서는 순열검정에서 생성하는 치환표본의 수가 많이 필요하고 시간이 오래 걸린다는 문제점이 있다. 순열검정을 대신할 모수적 방법들을 검토한 결과, 적률을 이용한 근사가 각 집합의 유의확률 계산시간도 훨씬 단축하며 순열검정에서 구한 유의확률과 크기와 순위가 거의 일치함을 확인하였다.

• Journal of Positioning, Navigation, and Timing
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• 제9권3호
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• pp.285-292
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• 2020

This paper introduces a new computational efficient Dilution of Precision (DOP)-based landmark exclusion method while ensuring the safety of the LiDAR-based navigation system that uses an innovation-based Nearest-Neighbor (NN) Data Association (DA) process. The NN DA process finds a correct landmark association hypothesis among all potential landmark permutations using Kalman filter innovation vectors. This makes the computational load increases exponentially as the number of landmarks increases. In this paper, we thus exclude landmarks by introducing DOP that quantifies the geometric distribution of landmarks as a way to minimize the loss of integrity performance that can occur by reducing landmarks. The number of landmarks to be excluded is set as the maximum number that can satisfy the integrity risk requirement. For the verification of the method, we developed a simulator that can analyze integrity risk according to the landmark number and its geometric distribution. Based on the simulation, we analyzed the relationship between DOP and integrity risk of the DA process by excluding each landmark. The results showed a tendency to minimize the loss of integrity performance when excluding landmarks with poor DOP. The developed method opens the possibility of assuring the safety risk of the Lidar-based navigation system in real-time applications by reducing a substantial amount of computational load.

• 한국통신학회논문지
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• 제32권4C호
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• pp.440-446
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• 2007

본 논문은 엘레멘트 인버스 처리에 근거한 재킷 변환을 통한 DFT 행렬의 새로운 표현을 다룬다. DFT 행렬의 역을 단지 재킷 변환의 소행렬 분해에 따라 표현하며 이러한 결과는 DFT 행렬의 역이 단지 이의 희소 행렬과 치환 행렬에만 관련됨을 보여준다. 재킷 행렬을 통한 DFT 행렬의 분해는 블록 변조 특성을 나타내는 강한 기하 구조를 갖는다. 이는 재킷 행렬을 통해 분해된 DFT 행렬은 블록 변조 과정으로 해석할 수 있음을 의미한다.

• ETRI Journal
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• 제38권2호
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• pp.326-336
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• 2016

We propose and describe new error control algorithms for redundant residue number systems (RRNSs) and residue number system product codes. These algorithms employ search techniques for obtaining error values from within a set of values (that contains all possible error values). For a given RRNS, the error control algorithms have a computational complexity of $t{\cdot}O(log_2\;n+log_2\;{\bar{m}})$ comparison operations, where t denotes the error correcting capability, n denotes the number of moduli, and ${\bar{m}}$ denotes the geometric average of moduli. These algorithms avoid most modular operations. We describe a refinement to the proposed algorithms that further avoids the modular operation required in their respective first steps, with an increase of ${\lceil}log_2\;n{\rceil}$ to their computational complexity. The new algorithms provide significant computational advantages over existing methods.

• Journal of Biosystems Engineering
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• 제38권3호
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• pp.199-207
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• 2013

Purpose: Tomatoes, an important agricultural product in fresh-cut markets, are sometimes a source of foodborne illness, mainly Salmonella spp. Growth cracks on tomatoes can be a pathway for bacteria, so its detection prior to consumption is important for public health. In this study, multispectral Visible/Near-Infrared (NIR) reflectance imaging techniques were used to determine optimal wavebands for the classification of defect tomatoes. Methods: Hyperspectral reflectance images were collected from samples of naturally cracked tomatoes. To classify the resulting images, the selected wavelength bands were subjected to two-band permutations, and a supervised classification method was used. Results: The results showed that two optimal wavelengths, 713.8 nm and 718.6 nm, could be used to identify cracked spots on tomato surfaces with a correct classification rate of 91.1%. The result indicates that multispectral reflectance imaging with optimized wavebands from hyperspectral images is an effective technique for the classification of defective tomatoes. Conclusions: Although it can be susceptible to specular interference, the multispectral reflectance imaging is an appropriate method for commercial applications because it is faster and much less expensive than Near-Infrared or fluorescence imaging techniques.

• 정보관리학회지
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• 제1권1호
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• pp.25-42
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• 1984

정보(情報)의 축적(蓄積)과 검색(檢索)을 위한 개념(槪念) 조직과정(組織過程)에서는 개념(槪念) 뿐만 아니라 이들 개념간(槪念間)의 상관관계(相關關係)가 명확히 표현되어야 하며 이를 위해서는 인간(人間)의 사고과정(思考科程)에 기초해야 한다. 연관색인법(聯關索引法)에서는 9개의 연관기호(聯關記號)를 통하여 문신 중에서 각 개념간의 관계표현이 가능하며 이들 개념을 순열(順列)시키므로써 주제색인(主題索引)으로서의 기능을 수행할 수 있으며 기존의 색인(索引)시스템에 비해 검색효율의 개선(改善)을 초래할 수 있을 것이다.

• 한국정보통신학회논문지
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• 제17권1호
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• pp.41-48
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• 2013

본 논문에서는 개인기반 클라우드 컴퓨팅 환경에서 복잡하고 시간이 많이 소요되는 3DES 알고리즘에 비해 기존의 DES 암호화 알고리즘을 기반으로 안정성과 속도를 개선한 알고리즘을 제안한다. 제안하는 알고리즘은 DES 알고리즘에 있어 안전성 측면에서 단점인 초기치환 및 최종치환을 위한 고정된 치환테이블을 스프레드 랜덤 인터리버 기법을 적용한 동적 치환박스를 적용하여 보안성을 제고하였다. 기존 알고리즘과의 시뮬레이션 결과 비교를 통해 제안하는 알고리즘을 활용할 경우 최소한의 변경으로 전달 데이터에 대한 기밀성과 안정성을 확보하고 빠른 속도로 암호화 및 복호화를 달성할 수 있음을 확인할 수 있었으며 CBC 모드를 적용하여 가변 길이의 데이터에 대해서도 효과적인 암호화가 가능하다.

• Earthquakes and Structures
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• 제17권5호
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• pp.477-487
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• 2019

Understanding the behavior of skew bridges under the action of earthquakes is quite challenging due to the combined transverse and longitudinal responses even under unidirectional hit. The main goal of this research is to assess the response of skew bridges when subjected to longitudinal and transversal earthquake loading. The effect of skew on the response considering two- and three- span bridges with skew angles varying from 0 to 60 degrees is illustrated. Various pier fixities (and hence stiffness) and cross-section shapes, as well as different abutment's bearing articulations, are also studied. Finite-element models are established for modal and seismic analyses. Around 900 models are analyzed under the action of the code design response spectrum. $Vis-{\grave{a}}-vis$ modal properties, the higher the skew angle, the less the fundamental period. In addition, it is found that bridges with skew angles less than 30 degrees can be treated as straight bridges for the purpose of calculating modal mass participation factors. Other monitored results are bearings' reactions at abutments, shear and torsion demand in piers, as well as deck longitudinal displacement. Unlike straight bridges, it has been typically noted that skew bridges experience non-negligible torsion and bi-directional pier base shears. In a complementary effort to assess the accuracy of the conducted response spectrum analysis, a series of time-history analyses are applied under seven actual earthquake records scaled to match the code design response spectrum and critical comparisons are performed.

• 한국수학사학회지
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• 제32권2호
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• pp.61-77
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• 2019

The study was conducted based on the 'method of mathematical exploration through history'. In recent school education, 'Probability and Statistics' education has been emphasized, and as a result, the study has conducted a study on permutations. Permutation is used in a variety of fields, and in this study, we looked at the Derangement. The results of this study are as follows. First, analysis was made at current school mathematics level and academic mathematics level for Derangement. Second, the historical development process of derangement was examined. Third, based on this, the research direction of this study was decided to be 'Derangement number's triangle(Rencontres number's triangle)', and the inquiry for education expansion was carried out. Fourth, we have presented data on concrete educational expansion by discovering various mathematical facts of the Derangement number's triangle. We hope that the results of this study will provide meaningful implications for the application of mathematics and the presentation of new inquiry directions.

• Journal of Forest and Environmental Science
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• 제37권1호
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• pp.14-24
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• 2021

A plant community is a group of populations that coexist in space and interact directly or indirectly with the environment. In this paper, we determined the pattern of tree species composition in response to soil variables in Khadimnagar National Park (KNP), which is one of the least studied tropical forests in Bangladesh. Soil and vegetation data were collected from 71 sample plots. Canonical Correspondence Analysis (CCA) with associated Monte Carlo permutation tests (499 permutations) was carried out to determine the most significant soil variable and to explore the relationship between tree species distribution and soil variables. Soil pH and clay content (pH with p<0.01 and Clay content with p<0.05) were the most significant variables that influence the overall tree species distribution in KNP. Soil pH is related to the distribution and abundance of Syzygium grande and Magnolia champaca, which were mostly found and dominant species in KNP. Some species were correlated with clay content such as Artocarpus chaplasha and Cassia siamea. These observations suggest that both the physico-chemical properties of soil play a major role in shaping the tree distribution in KNP. Hence, these soil properties should take into account for any tree conservation strategy in this forest.