• Proceedings of the KSR Conference
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• 2007.11a
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• pp.1858-1863
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• 2007

Railway systems are one of the best mass transit systems and many people have prevented incidents/accidents and reduced fatalities remarkably. Especially we have tried analyzing and finding the measures to prevent catastrophic accidents like train collision, derailment and fire because of their severities. It is important to assess the safety performances of railway systems like crash-worthiness analysis, body, derailment affecting factor analysis and so on for reducing and finding out the reasonable causes of disastrous accidents. In this paper the refined top-level system requirements to build-up national infra for assessing railway safety performance and the procedures and methodology for reviewing, verifying and validating infra requirements are explained. Basically the authors have used system engineering processes to analyze and verify the requirements and installation procedures and have tried maximizing the practicality of the various safety assessment systems.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.32 no.1
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• pp.147-156
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• 2009

The introduction and application of IT(Information Technology) to a company has become to be viewed as a key factor for the business competitiveness and improved productivity. This study presents an approach to evaluation of a company's informatization level, which is especially appropriate for small and medium enterprises. The proposed evaluation method, based on the traditional questionnaire approaches, considers the various characteristics of the company, e.g., types of business, characteristics of customers, and locations of supply chains etc. A web-based system was developed to enable users to obtain the evaluation results from the evaluation method. The system also provides a function to produce valuable strategies for informatization by utilizing the case base which will be cumulated by repetitive evaluation requests. Finally, a real case was analyzed in order to verify the practicality of the evaluation system.

• Safety and Health at Work
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• v.8 no.2
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• pp.226-230
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• 2017

The performance of sound barriers was evaluated to determine their technical effectiveness and practicality in reducing noise exposures to operating engineers in construction. Commercially purchased sound dampening mats (SDMats) were installed inside three heavy-equipment engine compartments. Sound pressure levels (SPLs) were measured before and after installing the SDMats while the equipment was on idle and full-throttle settings where it normally operates. SPLs inside the heavy-equipment operator cabs were significantly reduced by 5.6-7.6 dBA on the full-throttle setting following installation of the SDMats (p < 0.01). The evaluated engineering control intervention was simple to install, affordable, and substantially reduced the engine noise reaching the heavy-equipment operator, potentially reducing reliance on hearing-protection devices to protect construction workers from noise exposures.

• Journal of the Korean Society for Nondestructive Testing
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• v.26 no.1
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• pp.30-39
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• 2006

Feasibility is studied for an application of the mass-spring lattice model (MSLM), a numerical model previously developed for unidirectional composites, to the numerical simulation of ultrasonic inspection of austenitic welds modeled as transversely isotropic. Fundamental wave processes, such as propagation, reflection, refraction, and diffraction of ultrasonic waves in such an inspection are simulated using the MSLM. All numerical results show excellent agreement with the analytical results. Further, a simplified model of austenitic weld inspection has been successfully simulated using the MSLM. In conclusion, a great potential of the MSLM in numerically simulating ultrasonic inspections of austenitic welds has been manifested in this work, though significant further efforts will be required to develop a model with field practicality.

• 한국데이터정보과학회:학술대회논문집
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• 2004.04a
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• pp.91-101
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• 2004

The turbulent flow is of fundamental interest because the conservation equations for thermodynamics, mass and momentum are linked together. This turbulent flow consists of some coherent time- and space-organized vortical structures. Research has already shown that some dynamic systems and experimental models still cannot provide a good nonlinear analysis of turbulent time series. In the real turbulent flow, very complicated nonlinear behaviors, which are affected by many vague factors are present. In this paper, a kernel-based machine for fuzzy nonlinear regression analysis is proposed to predict the nonlinear time series of turbulent flows. In order to show the practicality and usefulness of this model, we present an example of predicting the near-wall turbulence time series as a verifiable model and compare with fuzzy piecewise regression. The results of practical applications show that the proposed method is appropriate and appears to be useful in nonlinear analysis and in fuzzy environments to predict the turbulence time series.

• Journal of Institute of Control, Robotics and Systems
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• v.19 no.11
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• pp.1048-1052
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• 2013

Recently, many countries have attempted to protect their satellites from damage caused by space debris. To design these collision avoidance maneuvers, optimal algorithms based on numerical simulations are widely used due to their practicality. However, these algorithms often require a great expenditure of time in order to find solutions. Therefore, in this paper, a simple analytical strategy is suggested to find the initial prediction required to find these numerical solutions for collision avoidance maneuvers by using relative dynamics for the rendezvous and docking problems. For this analytical strategy, the simple dynamics on the CW (Clohessy-Wiltshire) frame is adopted as an attempt to introduce an analytical solution.

• Proceedings of the IEEK Conference
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• 2002.06c
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• pp.131-134
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• 2002

As the increased use of computer, wired/wireless/mobile Internet, security in using Internet becomes a more important problem. Thus, biometric technology using physical and behavior characteristics of a person is hot issue. Many different types of biometric technologies of a person such as fingerprint, face, iris, vein, DNA, brain wave, palm, voice, dynamic signature, etc. had already been studied but remained unsuccessful because they do not meet social demands. However, recently many of these technologies have been actively revived and researchers have developed new products on various commercial fields. Dynamic signature verification technology is to verify the signer by calculating his writing manner, speed, angle, and the number of strokes, order, the down/up/movement of pen when the signer input his signature with an electronic pen for his authentication. Then signature verification system collects mentioned above various feature information and compares it with the original one and simultaneously analyzes to decide whether signature is forgery or true. The prospect of signature verification technology is very promising and its use will be wide spread in terms of economy, security, practicality, stability and convenience.

• Journal of Forest and Environmental Science
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• v.32 no.2
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• pp.182-188
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• 2016

In this study 'forest design in waterside unused land' of 'waterside area' in the specificity that multilateral, including landscape, recreation, social and environmental aspects in the space, taking into account by multiple factors :Raise 'practicality' than a functional management and police to hang out with, each element is usually way to improve the beauty. There is currently carried out waterside green area creation, which is artificial plantation and open spaces only emphasizing 'landscape' with lacking multi-function purpose, as a 'forest design in waterside unused land' strategy but it should be lowered by performance in this strategy. And the study suggested a strategy which prepared cultural and social infrastructure to be able to attract different fund and build local character as an alternative demand plan considered environmental character as a top priority.

• Proceedings of the KIEE Conference
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• 2006.04a
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• pp.252-254
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• 2006

The recent improvement in the performance of digital processor, the application of control technology, which used in the HVDC(High Voltage Direct Current) system with the digital processors, has increased. Having this research development as the basis, this paper presents an achievement of progression by tuning the parameter of PI controller based on Genetic Algorithms(GAs) and by controlling with PI controller with a developed simulator by applying the Matrix operating function, voltage source switching element, modified nodal analysis which can include transformer and the backward Euler which does not create the problem of numerical oscillation. As a result, I expect this development in the simulator HVDC System to bring more application in the field of control technology research with an expanded practicality.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.60 no.1
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• pp.13-18
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• 2011

More and all-electric aircraft (AEA) carry many loads with varied functions. In particular, there may be large pulsed loads with short duty ratios which can affect the normal operation of other loads. In this paper, a converter with spilt capacitors and an improved adaptive controller is used as the Voltage Bus Conditioner (VBC) with the reduced capacitive storage to mitigate the voltage transients on the bus. The proposed converter allows the smaller capacitive storage. Also, the proposed controller has the advantage of requiring only one sensor and performing both the functions of mitigating the voltage bus transients and maintaining the level of energy stored. Experimental results are presented which verify the control principles and demonstrate the practicality of the approach.