• Proceedings of the Korea Water Resources Association Conference
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• 2017.05a
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• pp.114-114
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• 2017

하천의 유사량 자료는 하상변동 예측, 저수지 퇴사량 추정, 유사조절 계획 수립 등 유역과 하천관리 그리고 하천 시설물 관리를 위해 필요하다. 최근 4대강 사업구간에 대한 담수용 보로 유입되는 유사량과 하천 유사의 종횡단적 분포와 하상변동량 등의 산정에 기초자료로 활용하고자 유사량 관측망이 구축되어 있다. 본 연구에서는 하천 유사량에 영향을 미치는 유역특성인자에 대한 군집분석을 통해 유사 발생 유역을 분류하고자 한다. 체계화된 유량 및 유사량 측정 방법에 의해 신뢰할만한 유량-총유사량 관계식을 갖는 유량조사사업단의 35개 유역을 대상으로 한다. 유역 군집분석을 수행하고자 유역과 하천에 대한 지형인자, 토양인자, 토지이용 등의 유역특성 매개변수 자료를 수집하였고, 매개변수별 유사도거리 산정에 오류를 줄이기 위해 매개변수를 무차원화 하였다. 유역의 비유사량은 유역면적, 유역경사, 토성, 토지이용 등에 영향을 받았다. K-means 기법에 의해 군집분석을 수행한 결과 유사량 측정 유역은 A, B, C, D 4개의 그룹으로 분류되었다. B그룹 유역은 첨두홍수량이 크고 발생시간이 짧은 유역 및 하천 조건을 가지고 있었으며, 직접유출이 증가하는 지표조건과 침식이 활발한 토양조건을 갖는 것으로 파악되었다. 그룹별로 실측 비유사량을 검토한 결과 B그룹에 포함된 유역의 유사량이 다른 유역에 비해 상대적으로 크게 발생하였다. 이러한 결과는 유역특성 매개변수의 군집분석을 통한 유역의 군집분류가 유역과 하천의 유사관리 측면에서 유용한 관리방안으로 활용될 수 있음을 의미한다.

• Journal of Ocean Engineering and Technology
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• v.28 no.1
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• pp.20-27
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• 2014

In view of the importance of material reduction and rational structural design due to the rapid increase in oil and steel prices, an optimized structural hybrid design system for the doubler plate of a ship's hull structure was developed. A direct design process by a structural designer was added to this developed optimized system to increase the design efficiency and provide a way of directly inserting a designer's decisions into the design system process. As the first step of the doubler design system development, the design formulas used in doubler design system were introduced. Based on the introduction of influence coefficients $K_{t_c}$ $K_{t_d}$, $K_{b_d}$ and $K_{a_d}$ according to the variations in the doubler length, breadth, doubler thickness, and average corrosion thickness of the main plate, the design formulas for an equivalent plate thickness were developed, and a hybrid design system using these formulas was suggested for the slender doubler plate of a ship structure subjected to a longitudinal in-plane compression load. By using this developed design system, a more rational doubler plate design can be expected considering the efficient reinforcement of the plate members of ship structures. Additionally, a more detailed structural analysis through local strength evaluations will be performed to verify the efficiency of the optimum structural design for the doubler plate.

• Journal of Korean Society for Quality Management
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• v.48 no.2
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• pp.269-282
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• 2020

Purpose: The practical design for experiments with mixtures of q components is consisted in the four types of design points, vertex, center of edge, axial, and center points in a (q-1)-dimensional simplex space. We propose a sequential method for the successful construction of the design space in Quality by Design (QbD) by allowing the different number of replicates at the four types of design points in the practical design when the quadratic canonical polynomial model is assumed. Methods: To compare the mixture designs efficiency, fraction of design space (FDS) plot is used. We search for the practical mixture designs whose the minimal half-width of the tolerance interval per a standard deviation, which is denoted as d₂, is less than 4.5 at 0.8 fraction of the design space. They are found by adding the different number of replicates at the four types of the design points in the practical design. Results: The practical efficient mixture designs for the number of components between three and five are listed. The sequential method to establish a design space is illustrated with the two examples based on the simulated data. Conclusion: The designs with the center of edge points replications are more efficient than those with the vertex points replication. We propose the sample size of at least 23 for three components, 28 for four components, and 33 for the five components based on the list of efficient mixture designs.

• Korean Chemical Engineering Research
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• v.46 no.4
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• pp.824-832
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• 2008

micellar solution which is comprised of surfactant monomers, monodisperse micelles, and solvent(water) is studied from a statistical-mechanical point of view. The model examined in this article is for the ideal mixture of monomers, micelles, and solvent with the dielectric constant identical to that of solvent, which is an assumption common to continuum models. The model also reflects interactions between monomer and solvent molecule, and also between micelle and solvent molecule. The statistical-mechanical model under consideration yields ln $X_{CMC}=A+BT+C/T+D{\ln}T$ with $X_{CMC}$ being critical mcielle concentration (in mole fraction), being temperature, and A, B, C, D being constants which depend on the properties of the surfactant molecules. The statistical-mechanical model discussed in this article provides a theoretical basis on the thermal dependence of critical micelle concentration

• Journal of Ocean Engineering and Technology
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• v.30 no.4
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• pp.294-302
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• 2016

Because of the importance of steel material saving and rational ship structural design due to the rapid increase in steel prices, a ship structural design system was developed for plate members reinforced by doubler plates subjected to biaxial in-plane compressive loads. This paper mainly emphasizes the design system improvement and upgrade according to the change in the in-plane loading condition of the doubler plate from the single load discussed in a previous paper to the biaxial in-plane compressive load discussed in this paper. A direct design process by a structural designer was added to this developed optimized system to increase the design efficiency and provide a way of directly inserting a designer's decisions into the design system process. As the second stage of preliminary steps of doubler design system development, design formulas subjected to these biaxial loads used in the doubler plate design system were suggested. Based on the introduction of influence coefficients $K_t_c$, $K_t_d$, $K_b_d$ and $K_a_d$ based on the variations in the doubler length, breadth, doubler thickness, and average corrosion thickness of the main plate reinforced by the doubler plate, respectively, the design formulas for the equivalent plate thickness of the main plate reinforced by the doubler plate were also developed, and a hybrid design system using these formulas was suggested for the doubler plate of a ship structure subjected to a biaxial in-plane compressive load. Using this developed design system for a main plate reinforced by a doubler plate was expected to result in a more rational reinforced doubler plate design considering the efficient reinforcement of ship plate members subjected to these biaxial loads. Additionally, a more detail structural analysis through local strength evaluations will be performed to verify the efficiency of the optimum structural design for a plate member reinforced by a doubler plate.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.14 no.5
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• pp.375-384
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• 2021

The development of the European Railway Traffic Management System (ERTMS) began in 1989 as part of the European Union policy to establish a unified and interoperable railway route in Europe. It is a trend that ERTMS/ETCS(European Train Control System) is becoming an international standard in the railway signaling system. As the solution to this situation, the domestic railway signaling field is also at a time when it is more necessary to develop the technology of the train control system considering interoperability. The European Railway Agency (ERA) has proposed B3R2 (Baseline 3 Release 2) for new ETCS-equipped trains after 2020.12.31. In Korea, Baseline 2.2.0 to 2.3.0d on Gyeongbu Line, Honam Line, Jeolla Line, and Gyeongchun Line was installed and now is under operating. As the Baseline upgrade continues, technical considerations and economic considerations are an occurring trend. In this paper, we analyzed the main functions and compatibility of the currently distributed European standard ERTMS/ETCS Baseline 3 and presented a plan to apply the domestic KTCS(Korean Train Control System) Baseline in the near future.

• Journal of the Korean Society for Library and Information Science
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• v.40 no.3
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• pp.175-190
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• 2006

For the recent several years, there has been much interest in lexical semantic network However it seems to be very difficult to evaluate the effectiveness and correctness of it and invent the methods for applying it into various problem domains. In order to offer the fundamental ideas about how to evaluate and utilize lexical semantic networks, we developed two automatic vol·d clustering systems, which are called system A and system B respectively. 68.455.856 words were used to learn both systems. We compared the clustering results of system A to those of system B which is extended by the lexical-semantic network. The system B is extended by reconstructing the feature vectors which are used the elements of the lexical-semantic network of 3.656 '-ha' verbs. The target data is the 'multilingual Word Net-CoroNet'. When we compared the accuracy of the system A and system B, we found that system B showed the accuracy of 46.6% which is better than that of system A. 45.3%.

• Journal of Korean Society of societal Security
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• v.2 no.2
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• pp.55-61
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• 2009

The statistics of disaster and safety control which have been produced by NEMA(National Emergency Management Agency) and other related agencies have some problems which show redundancies and the lack of connections. These problems can result in disbelief of disaster-management related policies and cause uncertainties on standardization. One of the main problems is caused by the lack of an integrated system that can coordinate available statistical resources. The objectives of this paper are to propose possible ways for the rearrangement of statistics categories, the improvement of statistics indicators and the integration of statistics of disaster and safety management based on the improvement of related laws and regulations. Through the integrated system for an efficient production of disaster and safety-related statistics, it will be possible to establish more accredited disaster-management policies based on the scientific statistics and international standard.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.34 no.12
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• pp.1871-1876
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• 2010

The reduction of vehicle interior noise has been the main interest of NVH engineers. The driver's perception of the vehicle noise is strongly affected by the psychoacoustic characteristics of the noise and the SPL. The existing methods to evaluate the SQ for vehicle interior noise are linear regression analysis of subjective SQ metrics by statistics and the estimation of subjective SQ values by neural network. However, these methods strongly depend on jury tests, this leads to difficulties. To reduce the important of the jury tests, we suggest a new method using the Mahalanobis distance for SQ evaluation. And, the optimal characteristic values that influenced the results of sound quality evaluation on the basis by main effect. Finally, we developed a new method based on the MD method to evaluate sound quality. The result of noise evaluation revealed that the sound quality could be well improved by changing the structural characteristics of the vehicle.

• Journal of the Korean Institute of Gas
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• v.4 no.3 s.11
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• pp.39-45
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• 2000

In general, most of the GIS only deal with materials and geometric data which just include position, radius, length of the structure. Therefore it's hard to get corrosion data from it. But the one that an owner of metallic structures want to know is the integrity of the structure. Cathodic Protection System can not protect corrosion on the underground facilities perfectly but protect corrsion effectively. It therefore is necessary to monitor the facilities continually So, we need the development of GIS interconnected a corrosion prediction system on the view point of the efficiency of operation and the protection for a big accident. The results of the development of its system are described in this paper. It can do life prediction and interference analysis and also newest corrosion data should be updated regularly.