• 한국철도학회논문집
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• 제7권4호
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• pp.326-331
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• 2004

A routing is the path that an actual trainset follows as it moves from one train to another train in a timetable. The number of routings is equivalent to the number of trainsets required to cover the timetable. The primary factors of rolling stock requirement plan include evaluating the minimum number of routings. This can be formulated as a set partitioning problem and solved using enumeration method or column generation method. In this paper we presents an enumeration algorithm which is useful to implement the enumeration method for the rolling stock requirement plan.

• 대한토목학회논문집
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• 제28권2B호
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• pp.177-185
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• 2008

적설분포의 정확한 모니터링은 일 기상 예측, 융설 유출 모델링과 동시에 기후와 지구의 연구에 중요한 요소이다. 융설 모형의 중요 매개변수인 적설분포면적은 실제 우리나라에서 적설과 관련한 관측 자료의 부족으로 인해 매개변수 추정이 어렵다. 이러한 문제점 해결을 위해 원격탐사기법을 활용하여 적설분포면적을 추출하였다. 본 연구에서는 1997년부터 2006년까지의 겨울철 NOAA AVHRR 위성영상의 8 sets의 총 108개 영상을 이용하여 적설분포면적을 추출하였고, 기상청의 지상기상관측소의 최심적설심 자료를 이용하여 GIS 자료를 구축함으로써 적설심의 공간적 분포를 추출하였다. 이를 이용하여 국내 주요 7개 댐유역에 대한 융설모형의 주요 매개변수인 적설분포면적, 유역 평균, 최대 적설심과 적설분포면적감소곡선을 구축하였다. 시간의 경과에 따른 적설면적의 감소는 지수함수적 감소곡선으로 표현이 가능하였으며, 곡선의 결정계수($R^2$)는 0.46~0.88의 범위를 보였다. 최대적설면적에서 10일이 경과하면 적설면적은 70-100% 감소하는 것으로 나타났다.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2005년도 Proceedings of ISRS 2005
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• pp.283-285
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• 2005

To account for the importance of variable in multi-sensor data fusion, random forests are applied to supervised land-cover classification. The random forests approach is a non-parametric ensemble classifier based on CART-like trees. Its distinguished feature is that the importance of variable can be estimated by randomly permuting the variable of interest in all the out-of-bag samples for each classifier. Supervised classification with a multi-sensor remote sensing data set including optical and polarimetric SAR data was carried out to illustrate the applicability of random forests. From the experimental result, the random forests approach could extract important variables or bands for land-cover discrimination and showed good performance, as compared with other non-parametric data fusion algorithms.

• Journal of Multimedia Information System
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• 제1권1호
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• pp.1-10
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• 2014

In this paper, we propose a new view synthesis technique for coding of multi-view color and depth data in arbitrary camera arrangements. We treat each camera position as a 3-D point in world coordinates and build clusters of those vertices. Color and depth data within a cluster are gathered into one camera position using a hierarchical representation based on the concept of layered depth image (LDI). Since one camera can cover only a limited viewing range, we set multiple reference cameras so that multiple LDIs are generated to cover the whole viewing range. Therefore, we can enhance the visual quality of the reconstructed views from multiple LDIs comparing with that from a single LDI. From experimental results, the proposed scheme shows better coding performance under arbitrary camera configurations in terms of PSNR and subjective visual quality.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2006년도 Proceedings of ISRS 2006 PORSEC Volume II
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• pp.848-851
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• 2006

Green vegetation is one of the most critical factors for environment conditions thorough modulating evapotranspiration and absorption of solar radiation. Thus, fractional green vegetation cover (FVC) plays an important role in observing and managing environment. Remote sensing provides a seemingly obvious data source for quantifying FVC over large area. Therefore we compared a set of methods for estimating FVC using hyperspectral remote sensing data. For our study, we used Hyperion imagery acquired in April, 2002. In order to achieve our efforts, we analyzed simple NDVI-based method and spectral mixture analysis (SMA) models that were applied a variety of combinations of possible endmembers.

• 한국수학교육학회지시리즈B:순수및응용수학
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• 제21권2호
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• pp.113-120
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• 2014

In this paper, we first show that for any space X, there is a ${\sigma}$-complete Boolean subalgebra of $\mathcal{R}$(X) and that the subspace {${\alpha}{\mid}{\alpha}$ is a fixed ${\sigma}Z(X)^{\sharp}$-ultrafilter} of the Stone-space $S(Z({\Lambda}_X)^{\sharp})$ is the minimal basically disconnected cover of X. Using this, we will show that for any countably locally weakly Lindel$\ddot{o}$f space X, the set {$M{\mid}M$ is a ${\sigma}$-complete Boolean subalgebra of $\mathcal{R}$(X) containing $Z(X)^{\sharp}$ and $s_M^{-1}(X)$ is basically disconnected}, when partially ordered by inclusion, becomes a complete lattice.

• Journal of applied mathematics & informatics
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• 제42권3호
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• pp.471-481
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• 2024

In this paper, the concept of D-sets will be applied to create D-lindelöf spaces, a new type of topological space covering the property. This is performed by using a D-cover, which is a special type of cover. The primary purpose of this work is to introduce the principles and concepts of D-lindelöf spaces. We look into their properties as well as their relationships with other topological spaces. The basic relationship between D-lindelöf spaces and lindelöf spaces, as well as many other topological spaces, will be given and described, including D-compact, D-countably compact, and D-countably lindelöf spaces. Many novel theories, facts, and illustrative and counter-examples will be investigated. We will use several informative instances to explore certain of the features of the Cartesian product procedure across D-lindelöf spaces as well as additional spaces under more conditions.

• 대한교통학회지
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• 제17권2호
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• pp.137-147
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• 1999

지금까지 시내버스 노선계획에 관한 대다수의 연구는 개별노선에 대한 지엽적인 분석을 바탕으로 하고 있으나 본 연구에서는 각 노선의 개별적 고려가 아닌 네트워크 차원의 최적화를 위한 노선계획 방법론을 제시하였다. 본 연구에서 제시하는 방법론은 계획가적 관점에서 버스이용자를 포함한 모든 통행자는 최단경로로 통행하기를 희망한다는 기본 전제하에 각 기종점의 최단경로로 구성된 대안 노선망을 도출하고 matrix 형태의 집합개념을 도입한 Set Covering 이론을 적용하여 노선공급수준을 축소하였다. 또한 노선축소과정에서 지금까지 부수적 통행요소로 인식되어온 환승을 활용하여 통행수요를 만족하는 최소규모의 노선망을 도출하였다. 본 연구는 고정수요를 가정하는 기존 연구와 달리 통행자 행태를 반영한 최적 노선망을 도출하기 위하여 시내버스 노선망 대안에 대한 가변수요를 구현하였다. 따라서 본 연구를 통하여 자가용이용자와 버스이용자로 구성된 전체 네트워크의 통행비용을 최소화하며 서비스 제공규모를 최소화하는 최적 시내버스 노선망을 도출하였다. 연구결과 기존연구와 비교하여 서비스 공급수준을 축소할 뿐 아니라 통행자의 행태를 고려한 해를 도출함으로써 현실성을 제고하였다.

• 한국컴퓨터정보학회논문지
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• 제18권5호
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• pp.113-120
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• 2013

본 논문은 지금까지 NP-완전인 난제로 알려진 4-색 정리를 $O(n)$선형시간 복잡도로 수기식과 컴퓨터를 활용하여 증명하는 알고리즘을 제안하였다. 제안된 알고리즘은 그래프 $G=(V_1,E_1)$의 정점 집합 V를 최대 독립집합 $\bar{C_1}$와 최소 정점 피복 집합 $C_1$으로 정확히 양분하는 기법을 적용하여 $\bar{C_1}$에 첫 번째 색을 배정하고, $C_1$ 집합의 정점들로 축소된 연결 그래프 $G=(V_2,E_2)$를 대상으로 $\bar{C_2}$와 $C_2$로 양분하여 $\bar{C_2}$에 두 번째 색을 지정하였다. $C_2$ 집합의 정점들로 축소된 연결 그래프 $G=(V_3,E_3)$를 대상으로 $\bar{C_3}$와 $C_3$로 양분하여 $\bar{C_3}$에 세 번째 색을 지정하였다. 마지막으로$C_3$를 $\bar{C_4}$로 하여 4번째 색을 배정하였다. 2개의 실제 지도 그래프와 2개의 평면 그래프를 대상으로 제안된 알고리즘을 적용한 결과 모든 그래프에서 채색수 ${\chi}(G)=4$를 찾는데 성공하였다. 결국, 제안된 "4-색 알고리즘"은 평면 그래프의 4-색을 결정하는 일반적인 알고리즘으로 적용할 수 있을 것이다.

• 한국작물학회:학술대회논문집
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• 한국작물학회 2017년도 9th Asian Crop Science Association conference
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• pp.344-344
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• 2017

The glycoprotein known as glomalin-related soil protein (GRSP) is abundantly produced on the hyphae and spores of arbuscular mycorrhizal fungi (AMF) in soil and roots. GRSP play a decisive role in the soil aggregation, but GRSP was also sensitive to agricultural managements. Thus, our objectives were to assess the effect of different cover crop incorporation on the GRSP content in soil and growth of subsequent soybean and maize. Pot experiments with the incorporation of four cover crops were set up. The same amount (666g) of aboveground plant parts of wheat (AMF host), hairy vetch (AMF host), mustard (non-host) and rapeseed (non-host) was separately incorporated into soils. The aboveground plant parts and roots of soybean and maize were grown in each incorporated pots and sampled at 6 and 9 weeks after sowing. Our results showed that the different cover crops incorporation affected soil biological and chemical properties such as EC, $NO_3-N$ content, ${\beta}-glucosidase$ activity, alkaline phosphatase (ALP) activity and GRSP content. The soil EC and $NO_3-N$ content in the hairy vetch, mustard and rapeseed was higher compared to the wheat. The ${\beta}-glucosidase$ activity in the wheat and hairy vetch was significantly higher than that in the mustard and rapeseed, and the ALP activity in the wheat was significantly higher than that in the hairy vetch, mustard, and rapeseed. The GRSP content in the mustard and rapeseed was significantly lower than that of the hairy vetch and wheat. Moreover, The top dry weight and leaf area of soybean and maize in the hairy vetch at 6 weeks were significantly higher compared to the other treatments. Our results indicated that the incorporation of mustard and rapeseed may cause indirectly the decrease of GRSP content and soil enzyme activity in soil. One possible explanation for the decrease of GRSP in non-AMF host crop treatments may be the decrease of AMF density in the soil. AMF are not able to form a symbiotic relationship with Brassicaceae roots due to the release of anti-fungal compounds. This means the AMF may not be able to produce GRSP in the soil. However, the differences in the benefit of cover crop incorporation were shown only by a pot experiment. Comparative investigations of crop residue managements would be applied to both pot experiment and field study to clarify a better selection of cover crops in rotation to encourage GRSP production.