• Proceedings of the Korea Water Resources Association Conference
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• 2023.05a
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• pp.51-51
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• 2023

최근 기후의 급격한 변화 및 이상기후로 인해 전 세계적으로 가뭄의 발생빈도가 증가하고 있는 추세이다. 우리나라의 경우 지역·계절별 강수량의 편차로 인해 국지적으로 극심한 가뭄이 발생하고 있으며, 향후 피해는 더욱 증가할 것으로 예측하고 있다. 농업가뭄은 농작물 생육에 따른 수확량 및 수자원 이용에 직접적인 영향을 미치고 있으며, 농업수리시설물의 의존도가 높기 때문에 저수지의 대응능력과 농경지의 수리답 시설이 농업가뭄 대응을 위한 중요한 지표로써 활용되고 있다. 본 연구에서는 수리시설물의 가뭄대응능력과 평야부 농경지의 가뭄빈도를 이용하여 농업가뭄 취약성 평가를 수행하였다. 2015년 이후 매년 가뭄이 발생하는 충청남도 태안군을 시범지역으로 선정하였으며, 논 중심의 농업가뭄을 평가하기 위해 기상영향, 가뭄발생현황, 보조수원능력, 가뭄대응능력 4가지의 관련 항목을 선정하였다. 기상영향, 가뭄발생현황, 보조수원현황 항목은 계수화를 위해 데이터 속성 정보만을 이용하여 가중치를 산정하는 엔트로피 (Entropy) 방법을 적용하였으며, 가뭄대응능력 항목은 농업수리시설물과 농경지 평균 가뭄빈도 분석을 통해 점수화를 수행하였다. 본 연구의 결과는 지역별로 선제적인 가뭄대응 우선순위를 결정할 수 있고, 용수공급의 효율화 등 논 중심의 농업가뭄 대응을 위한 기초자료로써 활용될 수 있을 것으로 판단된다.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.19 no.4 s.74
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• pp.429-440
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• 2006

This paper comprises two specific objectives. The first is to examine the applicability of ordinary kriging interpolation(OK) to the p-adaptivity of the finite element method that is based on variogram modeling. The second objective Is to present the adaptive procedure by the hierarchical p-refinement in conjunction with a posteriori error estimator using the modified S.P.R. (superconvergent patch recovery) method. The ordinary kriging method that is one of weighted interpolation techniques is applied to obtain the estimated exact solution from the stress data at the Gauss points. The weight factor is determined by experimental and theoretical variograms for interpolation of stress data apart from the conventional interpolation methods that use an equal weight factor. In the p-refinement, the analytical domain has to be refined automatically to obtain an acceptable level of accuracy by increasing the p-level non-uniformly or selectively. To verify the performance of the modified S.P.R. method, the new error estimator based on limit value has been proposed. The validity of the proposed approach has been tested with the help of some benchmark problems of linear elastic fracture mechanics such as a centrally cracked panel, a single edged crack, and a double edged crack.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.41 no.3
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• pp.27-36
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• 2004

Detection and recognition of human faces in images can be considered as an important aspect for applications that involve interaction between human and computer. In this paper, we propose a face recognition method using eigenfaces and fuzzy neural networks. The Principal Components Analysis (PCA) is one of the most successful technique that have been used to recognize faces in images. In this technique the eigenvectors (eigenfaces) and eigenvalues of an image is extracted from a covariance matrix which is constructed form image database. Face recognition is Performed by projecting an unknown image into the subspace spanned by the eigenfaces and by comparing its position in the face space with the positions of known indivisuals. Based on this technique, we propose a new algorithm for face recognition consisting of 5 steps including preprocessing, eigenfaces generation, design of fuzzy membership function, training of neural network, and recognition. First, each face image in the face database is preprocessed and eigenfaces are created. Fuzzy membership degrees are assigned to 135 eigenface weights, and these membership degrees are then inputted to a neural network to be trained. After training, the output value of the neural network is intupreted as the degree of face closeness to each face in the training database.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.7B
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• pp.991-1000
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• 2010

The Hierarchical Mobile IPv6 (HMIPv6) has been proposed to accommodate frequent mobility of the Mobile Node. HMIPv6 can effectively reduce the signaling overhead and latency. However, it has a problem that the registration of a mobile node concentrates on the furthest MAP(Mobility Anchor Point) when the mobile node enters into a new domain. This paper proposes a new load distribution mechanism by using the concept of Nash Bargaining Solution. The main advantage of the proposed scheme can prevent load concentration from being registered to the specified MAP based on the weight value according to the available resource-ratio of a MAP. With a simulation study, the proposed scheme can improve network performance under widely diverse traffic load intensities.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.2
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• pp.153-159
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• 2019

Job creation is the most important issue in the labor market these days, and the quality of jobs is also very important in order to resolve the mismatches that are taking place in the labor market. Kim Young-min (2014) developed the "2012 Quality of Employment Index" with twenty indicators in seven categories, including employment opportunities, to objectively assess the local labor market. This method presents the concept of the aggregate indicator, 'Quality of Work Index', and has the advantage of being easy to produce. However, it is difficult to statistically verify the adequacy of the constitutive indicators and, based on this, make them a single aggregate index through statistical techniques. Therefore, we developed an alternative '2012 Descent Work Index' and a confidence interval using Principal Component Analysis(PCA) and Unobserved Component Model(UCM) presented by Gi-Choon Kang & Myung-jig Kim (2014) and also calculated an alternative '2017 Descent Work Index' using the first half of 2017 local area labour force survey and compared its changes by region. The results of the empirical analysis show that the rank correlation coefficient between two methods of aggregating indicators, simple weight used in Young-min Kim's research, PCA method and UCM used in this study, were found to be statistically significant under 5% significance level. This implies that all methods are found to be useful. However, the PCA and UCM which determine scientific and objective weights based on data are preferred to Young-min Kim's approach. Since it provides us not only the level of aggregate indicator but also its confidence intervals, it is possible to compare ranking with the consideration of statistical significance. Therefore, it is expected that the method of constructing an aggregating indicator using UCM will be widely used in many areas in the future.

• Journal of Korea Multimedia Society
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• v.12 no.7
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• pp.1022-1031
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• 2009

In this paper, we propose a researcher modeling technique based on ontology and construct social network for researchers using diverse relational properties. User ontology schema is created by extending the existing HR-XML model for a researcher model. User ontology schema and instance are created by OWL. We compose social network model for efficient cooperation between researchers using static relational properties such as educational background and dynamic relational properties such as co-authors and co-workers, etc. Closeness has direction because researcher network is differently configured by the researchers. We define inferencing rules using SWRL and inference ontology rules using racer inference machine to compose direct relationships between researchers. The proposed model for researchers can be applied to the cooperation model for researchers by retrieving common expert group dynamically.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.28 no.7
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• pp.580-583
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• 2017

To compensate the degraded SAR image due to the residual errors and the spatial variant errors remaining after the motion compensation in the airborne SAR, we have introduced the autofocus method based on the partition processing. Thus, after we perform the spatial partition for the spotlight SAR data and the time partition for the stripmap SAR data, we reconstruct the subpatch images for the partitioned data. Then, we perform the local autofocus with the suitability analysis process for the phase errors estimated by the autofocus. Moreover, if the estimated phase errors are not properly compensated for the subpatch images, we perform the phase compensation method with the weight to the estimated phase error close to the degraded subpatch image to increase the SAR image quality.

• Journal of Korean Tunnelling and Underground Space Association
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• v.17 no.5
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• pp.553-561
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• 2015

In this study, the performance assessment criterion for reasonable maintenance of shield TBM tunnel was presented. The performance assessment items such as crack, leakage, breakage, spalling, exfoliation/detachment, efflorescence, quality condition, exposure of steel, carbonation, faulting step, bolts condition, drainage condition, ground condition, contact section condition and conduit condition were selected by analyzing domestic and foreign performance assessment criterions and investigating segment lining deterioration cases through the site investigation and in-depth inspection analysis result on the shield TBM tunnel. In addition, the reasonable weight using AHP (Analytic Hierarchy Process) were estimated.

• The KIPS Transactions:PartC
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• v.12C no.3 s.99
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• pp.387-394
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• 2005

Every MAC (Medium Access Control) sub-layers of IEEE 802.11x, including IEEE 802.11e, defines Connection-based and CF (Contention Free)-based service functions in common. In this paper, a New-CF method is proposed. In the proposed method, conventional Round Robin method, which is used as a polling method by IEEE 802.11x PCF (Point Coordination Function) or IEE 802.11e HCCA, is modified to give weights to channels with heavier traffic load and to provide those weighted channels with more services. Based on NS-2 simulations, it is verified the proposed method shows better throughput in general, particularly under unbalanced traffic load conditions.

• KIPS Transactions on Computer and Communication Systems
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• v.5 no.3
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• pp.47-54
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• 2016

In this paper, we propose a new opportunistic routing scheme based on timed bargaining game. The proposed algorithm effectively formulates the opportunistic routing mechanism as an repeated bargaining model using timed learning method. Additionally, we formulate a new contention window adjusting scheme for reduce collision rate. Simulation results indicate that the proposed scheme has excellent performance than other existing schemes under widely diverse VANET environments.