• Proceedings of the Korea Water Resources Association Conference
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• 2012.05a
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• pp.500-504
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• 2012

하구부에서의 점착성 유사의 이동량(유사량)은 조류의 비대칭성, 파랑, 하천 흐름, 조류 유속과 수위의 불일치성, 유사특성, 응집현상, 하상 침식율, 바닥지형 등 많은 인자의 영향을 받는다. 본 연구는 이들 인자들이 어떻게 영향을 주는지 살펴보기 위해 점착성 유사의 이동을 모의하는 1DV 모형을 이용하여 수치실험을 실시하고 그 결과를 분석하는 것이 목적이다. 점착성 유사의 실측자료가 부족한 실정과 현상에 대한 원인을 체계적으로 연구하는 방법을 참고하여 이상적인 조류조건을 가정하고 수치모형을 적용하였다. 점착성 유사의 특성을 고려하기 위해 응집현상이 고려되었고 가변적인 한계소류력이 적용되었다. 모의 결과를 통해서 조류의 한 주기 동안 이동하는 점착성 유사량은 가는 비점착성 유사의 이동량에 비해 조류 유속의 왜곡도에 영향을 덜 받을 수 있다는 결론이 도출되었다. 이러한 점은 가변적인 한계소류력에 기인하는 것으로 고려되며, 점착성 유사의 이동량을 연구하는 경우 가변적인 한계소류력이 고려되어야 한다는 점을 알 수 있다. 조류의 유속이 왜곡된 경우 하천으로부터 유하하는 유량이 크지 않은 경우 유사량의 방향이 조류 1 주기의 평균방향과 다를 수 있다는 결론 역시 도출된다. 조류의 수위와 유속 사이의 위상차가 유사량에 큰 영향을 주는 것으로 나타났다. 위상차가 무시되는 진행파 형태의 조류의 경우 큰 유사량을 나타내지만 약 $90^{\circ}$의 위상차를 나타내는 정상파의 경우는 무시할 정도의 유사량이 계산되었다. 위상차가 하구부의 형태에 따라서 결정된다는 점을 생각할 때 자연적 변화, 인위적 공사 등에 따라 하구부의 형태적 변화가 발생하는 경우는 유사량의 변화 역시 고려되어야 한다는 점을 알 수 있다. 이상적인 조건에서 수행된 본 연구의 보다 객관적인 검증을 위해 Ems/Dollard 하구부에서 측정된 수위, 유속, 부유사 농도 자료와 비교하였다. 그 결과 본 연구의 이상적인 조건과 유사한 특성을 나타낸다는 점을 알 수 있었고 본 연구의 결과가 자연에서 나타나는 현상의 특성을 대변할 수 있을 것으로 유추된다.

• Journal of Korea Water Resources Association
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• v.45 no.2
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• pp.165-178
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• 2012

The objective of this study is to evaluate the applicability of Land Surface Model (LSM) for estimating the runoff on East Asia. Global geographical and weather data are used as input for the model and for the model verification, the simulated runoff results are compared with observed data from 34 global observation stations provided by Global Runoff Data Center (GRDC). K$\ddot{o}$ppen's climate zone is used to calculate the model parameter for ungaged basins. As a result, the simulated runoff shows good performance comparing with observed data in 17 basins assumed as ungaged basins. The Hydrologic components on East Asia area are estimated from the model and the continental water balance components are seasonally similar to each country. Also, it reveals that runoffs from southern China, Japan and Taiwan are much higher than those from mongolian and northern China.

• KIPS Transactions on Computer and Communication Systems
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• v.9 no.4
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• pp.83-88
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• 2020

In Solar-powered wireless sensor networks(SP-WSN), the battery is periodically charged, so the best use of harvested energy is more important, rather than minimizing energy consumption. Meanwhile, as is well known, the reliability of communication between sensor nodes is very limited due to the resource-constraint of sensor nodes. In this paper, we propose an advanced FEC (forward error correction) scheme which can give SP-WSN more reliability for communication. Firstly, the proposed scheme uses energy modeling to calculate the amount of surplus energy which can be utilized for extra operations, and then determines the number of additional parity bits according to this amount of surplus energy. At the same time, link quality modeling calculates the optimal parity bits for error recovery in the current data communication environment. Finally, by considering these two parity sizes, it is possible to determine the optimal parity size that can maximize the data reliability without affecting the node black out. Performance verification was performed by comparing the amount of data collected at the sink and the number of outage nodes with other schemes.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.17 no.10 s.113
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• pp.929-934
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• 2006

In the paper, we suggest a simpler synthesis technique for capacitively-coupled match circuit(CCMC) which have a function of DC block and impedance matching simultaneously, and introduce a stability margin analysis technique for designing microwave amplifier under conditionally stable state. Stability margin analysis is used to determine optimum match point that ensure maximum gain under the given stability margin. It can reduce time consuming work for selecting match points in the conditionally stable state. Also, suggested miniaturization scheme of matching network is distinguished from previous work with respect to reducing deterministic parameters for CCMC synthesis. To verify utility of suggested method, 24 GHz gain block is fabricated under conditionally stable state using an internal thin-film fabrication process, Measured results show a stable gain of 10 dB and flatness of 1 dB, which is well coincident with simulated one.

• Journal of Korean Tunnelling and Underground Space Association
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• v.4 no.4
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• pp.261-276
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• 2002

Recently, for the purpose of choosing reasonable and economical construction, the decision making analyses, such as VE (Value Engineering) and LCC (Life Cycle Cost), are generally performed. But, these methods have some limitations for the application to subway tunnel construction method. So, the AHP (Analytical Hierarchy Process) analysis is applied to determine relative importance for obtaining objectivity in quantitative analysis. And, the LCSC (Life Cycle Social Cost) method is developed to account for the social loss and risk by tunnel construction. From the case of the subway ${\bigcirc}{\bigcirc}$ lot, those methods are very useful to decision making analysis. And, in that case, both quantitative and quantitative analysis appraisement, the drilling and blasting method is evaluated useful alternative proposal in comparing with the cut and cover method.

• Journal of the Korea Computer Industry Society
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• v.2 no.10
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• pp.1355-1364
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• 2001

Internal control comprises the plan of Organization and all of the coordinate methods and measure adopted within a business to safeguard its assets. check the accuracy and reliability of its accounting data, promote operation efficiency, and encourage adherence to prescribed managerial policies. Internal accounting control is classified into General Control and Application Control. Essential elements of internal accounting control as follows : 1. General Control $\circled1$ Organization and operation controls. $\circled2$ System development and Documentation controls. $\circled3$ Hardware controls. $\circled4$ Software and hardware Accessibility controls. $\circled5$ General systems security and protection 2. Application control $\circled1$Input control. $\circled2$ Processing control. $\circled3$ Output control. Internal accounting control can establish a total management information system by connecting with mana-gement control of a company, and enable decision makers to establish decision support system(DSS), is so vital today.

• Journal of Korea Multimedia Society
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• v.13 no.8
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• pp.1115-1127
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• 2010

In order to increase the productivity in manufacturing TFT-LCD(thin film transistor-liquid crystal display), it is essential to classify defects that occur during the production and make an appropriate decision on whether the product with defects is scrapped or not. The decision mainly depends on classifying the defects accurately. In this paper, we present an effective classification method for film defects acquired in the panel production line by analyzing the intensity distribution and shape feature of the defects. We first generate a binary image for each defect by separating defect regions from background (non-defect) regions. Then, we extract various features from the defect regions such as the linearity of the defect, the intensity distribution, and the shape characteristics considering intensity, and construct a referential image database that stores those feature values. Finally, we determine the type of a defect by matching a defect image with a referential image in the database through the matching cost function between the two images. To verify the effectiveness of our method, we conducted a classification experiment using defect images acquired from real TFT-LCD production lines. Experimental results show that our method has achieved highly effective classification enough to be used in the production line.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.16 no.3
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• pp.229-236
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• 2003

Artificial neural network has been used for damage assessment by many researchers, but there are still some barriers that must be overcome to improve its accuracy and efficiency. The major problems associated with the conventional artificial neural network, especially the Back Propagation Neural Network(BPNN), are on the need of many training patterns and on the ambiguous relationship between neural network architecture and the convergence of solution. Therefore, the number of hidden layers and nodes in one hidden layer would be determined by trial and error. Also, it takes a lot of time to prepare many training patterns and to determine the optimum architecture of neural network. To overcome these drawbacks, the PNN can be used as a pattern classifier. In this paper, the PNN is used numerically to detect damage in a plate girder railway bridge. Also, the comparison between mode shapes and natural frequencies of the structure is investigated to select the appropriate training pattern for the damage detection in the railway bridge.

• Journal of KIISE
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• v.44 no.7
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• pp.686-691
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• 2017

Telemarketing has become the center of marketing action of the industry in the information society. Recently, machine learning has emerged in many areas, especially, financial prediction. Financial data consists of lots of unlabeled data in most parts, and therefore, it is difficult for humans to perform their labeling. In this paper, we propose a fusion method of semi-supervised learning for automatic labeling of unlabeled data to predict telemarketing. Specifically, we integrate labeling results of label propagation and co-training with a decision tree. The data with lower reliabilities are removed, and the data are extracted that have consistent label from two labeling methods. After adding them to the training set, a decision tree is learned with all of them. To confirm the usefulness of the proposed method, we conduct the experiments with a real telemarketing dataset in a Portugal bank. Accuracy of the proposed method is 83.39%, which is 1.82% higher than that of the conventional method, and precision of the proposed method is 19.37%, which is 2.67% higher than that of the conventional method. As a result, we have shown that the proposed method has a better performance as assessed by the t-test.

• Journal of Korean Society of Steel Construction
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• v.14 no.4
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• pp.539-547
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• 2002

The study proposed the initial equilibrium state analysis method that considers axial deformation, in order to accurately determine the initial shape of a cable-stayed bridge. Sepecifically, the proposed method adopted the successive iteration method. In order to evaluate appropriate initial cable force introduced in the initial equilibrium state analysis, parametric studies were performed and a useful linear analysis method proposed. The geometrically nonlinear static behaviors of cable-stayed bridges were considered, using three-dimensional frame element and elastic catenary cable element. The usefulness and applicability of the analytic method proposed in this study were demonstrated using numerical examples, including a real cable-stayed bridge. The algorithm, is applicable in cases wherein axial deformation is not adopted in the fabrication camber, or final cable force is adjusted to eliminate construction and fabrication errors occurring during construction.