• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2014.10a
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• pp.966-972
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• 2014

The Lattice Boltzmann Method (LBM) has attracted attention as an alternative numerical algorithm for solving fluid mechanics, and its intrinsic unsteadiness and weak numerical damping make it more suitable for aeroacoustic problems. In this paper, applicability of the LBM for solving flow noise problems is tested by applying it to predict transmission loss of a simple expansion silencer. The time history of the static pressure is recorded at the inlet and outlet pipes. The transmission loss (TL) of the muffler is computed by using three point method and two source method, respectively. The TL calculated using the LBM is compared with that computed using finite element method (FEM) and measured data. It is found through these comparisons that the LBM is capable of predicting TL of the simple expansion silencer accurately, which it is difficult to predict using the conventional CFD methods based on the RANS solvers.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.11 no.7
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• pp.1387-1393
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• 2007

Even if the linearly separable patterns can be classified by the conventional single layer perceptron, the non-linear problems such as XOR can not be classified by it. A fuzzy single layer perceptron can solve the conventional XOR problems by applying fuzzy membership functions. However, in the fuzzy single layer perception, there are a couple disadvantages which are a decision boundary is sometimes vibrating and a convergence may be extremely lowered according to the scopes of the initial values and learning rates. In this paper, for these reasons, we proposed an enhanced fuzzy single layer perceptron algorithm that can prevent from vibration the decision boundary by introducing a bias term and can also reduce the learn time by applying the modified delta rule which include the learning rates and the momentum concept and applying the new linear activation function. Consequently, the simulation results of the XOR and pattern classification problems presented that the proposed method provided the shorter learning time and better convergence than the conventional fuzzy single layer perceptron.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2000.10a
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• pp.438-443
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• 2000

A wide range of problems geotechnical engineering have been analyzed by using the finite element method. In order to establish confidence in a numerical procedure, it is desirable that numerical solution be verified against field or laboratory observations, or both, and in order to aid the user in applying the method to practical problems, it is necessary to examine effects of various parameters that influence the behavior of engineering structures. Often it can be profitable to translate numerical solutions in formats that can be used readily for design analysis. The allowable bearing capacity of concrete piles is mainly governed by settlement rather than by strength of soil. Therefore, the load-displacement behavior of piles should be well understood at the design stage. This paper deals with some of these goals by considering the problem of load-displacement behavior of axially-loaded pile foundations.

• THE INTERNATIONAL COMMERCE & LAW REVIEW
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• v.51
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• pp.359-389
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• 2011

The Rotterdam Rules, which was adopted in December 2008 by UNCITRAL, has underlying intention that it will provide uniform law for the international carriage of goods by sea and modernize transport law reflecting modern transport custom. However, it is also true that there are various conflicting views on the Rotterdam Rules. This article tried to analyze main controversial issues such as scope of application, basis of liability of the shipper and the carrier, exception th the volume contract, legal position of the freight forwarder, delivery of the goods from the both sides of view. The Rotterdam Rules exposes some problems in applying and interpreting the Rules as many people indicated. These problems, I think, mainly due to the extended scope of application and broader range of issues. However, I do not think that the Rotterdam Rules will serious affect to the international transport industry. Furthermore, it is unreasonable to expect perfect Rules satisfying every interests.

• 제어로봇시스템학회:학술대회논문집
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• 1996.10b
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• pp.876-879
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• 1996

The vibration of an attractive magnetic levitation(Maglev) vehicle transportation system is caused by the irregularity of the guideway track and the performance of the suspensions of the Maglev system. It is essential for us to give attention to the secondary suspension of the vehicle system as it determines the ride quality. In order to improve the ride quality and running stability, active secondary suspensions have been developed and applied to the vibration problems. This paper analyzes the performance of the active secondary suspension which is applied to an attractive magnetic levitation vehicle system running on a rough track. The dynamics of the suspension system and the optimal control problems are studied. According to the transient and frequency response analyses to the track disturbance, the ride quality of an attractive Maglev vehicle has been improved by applying the designed LQR active controller, and it has been confirmed that this improvement was also influenced by the configuration of the system.

• International journal of advanced smart convergence
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• v.9 no.3
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• pp.59-70
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• 2020

There are many limitations in applying agile methodology to projects so far. In fact, projects overlap with other development methodologies and management processes, resulting in confusing progress, while there are often cases where the benefits of agile cannot be embraced due to a lack of understanding of agile processes and the organization's inability to adapt to change. It is an important role of information system development to improve the quality of agile application projects by discovering the problems and improvements in these cases. In this paper, we analyze the differences between existing development and project management methods and agile, and analyze agile processes. The optimal agile methodology was proposed by analyzing and applying methodologies established and applied mainly by large domestic development companies. In addition, the effectiveness was verified through a questionnaire of IT experts, and the result of the questionnaire was verified to be 4.75 points on a 5-point scale.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2019.11a
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• pp.197-198
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• 2019

In this study, the study was conducted to derive the utility of the safety management system applying block chain technology and big data technology to improve the problems of construction sites where concealment and operation of safety accidents occur. If block chain technology and big data technology are applied to construction safety management, transparent data can be collected, and based on the collected data, it is possible to predict accidents that can occur at the construction site and establish countermeasures. It can also be an opportunity to strengthen the safety awareness of construction workers and managers, and can clearly identify the responsibility in the event of a safety accident. This study suggests that the application of the 4th Industrial Revolution technology could be a great opportunity to innovate the construction industry which is less than other industries.

• Journal of Institute of Control, Robotics and Systems
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• v.13 no.11
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• pp.1040-1047
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• 2007

This paper presents ripple-free method that can occur in multirate controller design. The conventional multirate input controller has the problem that the ripple occurs in track-following because of chattering phenomenon in control input signal. In order to resolve the problem of rippling, it was proposed to eliminate the ripple phenomenon using feedforward compensator. This paper makes explains problems in conventional ripple-tree multirate controller and introduces a multirate controller design method applying lifting technique based on current estimators in condition space. Using the ripple-tree multirate controller, we show that chattering does not occur in the control input signal through applying the final value theorem from the viewpoint of discrete-time transformation. Also, this study proves that the ripple of the proposed controller decreases with the increase of this sampling frequency and, when sampling frequency is fixed, it decreases with the increase of the control input period.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2012.11a
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• pp.197-198
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• 2012

If the mechanical development be applied to the Nuclear Power Plant Structures instead of the standard hook development, the problem of overcrowding re-bars in the anchorage zone can be solved and the construction quality of the concrete work will be improved. But there are some problems in applying it to the NPP structures because of the restriction on the re-bar yield strength and diameter. After the performance evaluation test for the mechanical development, we can develop the new design equation of the mechanical development length in order to solve the limitation and apply it to NPP structures.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.36 no.6
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• pp.390-395
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• 1987

There is a variety not only of research topics but also of research techniques in electric power problems. It is well known that a significant increase in the rate of convergence can be obtained for the Gauss-Seidel method using the bus admittance matrix by applying acceleration factors determined empirically. The acceleration factor is calculated theoretically by using the bus voltage sensitivity (buses voltage interact each other) in this paper. It is observed that the proposed method using calculated acceleration factor gives better results than those of the method using calculated acceleration factor gives better results than those of the method using empirical one.